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Collatz conjecture

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1419: 1478: 1407: 1462: 7834: 1490: 2183: 6643: 140: 7822:(closely related to the Collatz conjecture) is false. Hence if BB(15) was known, and this machine did not stop in that number of steps, it would be known to run forever and hence no counterexamples exist (which proves the conjecture true). This is a completely impractical way to settle the conjecture; instead it is used to suggest that BB(15) will be very hard to compute, at least as difficult as settling this Collatz-like conjecture. 180: 156: 132: 59: 6520: 172: 5236: 6561: 4398: 1151: 6258: 1588:.) This yields a heuristic argument that every Hailstone sequence should decrease in the long run, although this is not evidence against other cycles, only against divergence. The argument is not a proof because it assumes that Hailstone sequences are assembled from uncorrelated probabilistic events. (It does rigorously establish that the 1418: 4282: 93:, the next term is one half of the previous term. If the previous term is odd, the next term is 3 times the previous term plus 1. The conjecture is that these sequences always reach 1, no matter which positive integer is chosen to start the sequence. The conjecture has been shown to hold for all positive integers up to 2385: 4779: 3936:
The Collatz map can be extended to (positive or negative) rational numbers which have odd denominators when written in lowest terms. The number is taken to be 'odd' or 'even' according to whether its numerator is odd or even. Then the formula for the map is exactly the same as when the domain is the
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Modifying the condition in this way can make a problem either harder or easier to solve (intuitively, it is harder to justify a positive answer but might be easier to justify a negative one). Kurtz and Simon proved that the universally quantified problem is, in fact, undecidable and even higher in
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contiguous subsequences, each consisting of an increasing sequence of odd numbers, followed by a decreasing sequence of even numbers. For instance, if the cycle consists of a single increasing sequence of odd numbers followed by a decreasing sequence of even numbers, it is called a
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stated in 2010 that the Collatz conjecture "is an extraordinarily difficult problem, completely out of reach of present day mathematics". However, though the Collatz conjecture itself remains open, efforts to solve the problem have led to new techniques and many partial results.
108:, who introduced the idea in 1937, two years after receiving his doctorate. The sequence of numbers involved is sometimes referred to as the hailstone sequence, hailstone numbers or hailstone numerals (because the values are usually subject to multiple descents and ascents like 6515:{\displaystyle {\begin{aligned}f(z)\triangleq \;&{\frac {z}{2}}\cos ^{2}\left({\frac {\pi }{2}}z\right)+{\frac {3z+1}{2}}\sin ^{2}\left({\frac {\pi }{2}}z\right)\,+\\&{\frac {1}{\pi }}\left({\frac {1}{2}}-\cos(\pi z)\right)\sin(\pi z)+h(z)\sin ^{2}(\pi z)\end{aligned}}} 3756:
An extension to the Collatz conjecture is to include all integers, not just positive integers. Leaving aside the cycle 0 β†’ 0 which cannot be entered from outside, there are a total of four known cycles, which all nonzero integers seem to eventually fall into under iteration of
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If the conjecture is false, it can only be because there is some starting number which gives rise to a sequence that does not contain 1. Such a sequence would either enter a repeating cycle that excludes 1, or increase without bound. No such sequence has been found.
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For the special purpose of searching for a counterexample to the Collatz conjecture, this precomputation leads to an even more important acceleration, used by TomΓ‘s Oliveira e Silva in his computational confirmations of the Collatz conjecture up to large values
472: 5630: 5539: 2215: 4625: 4561: 4277: 2491: 1670: 689: 4791: 5748: 4393:{\displaystyle {\frac {151}{47}}\rightarrow {\frac {250}{47}}\rightarrow {\frac {125}{47}}\rightarrow {\frac {211}{47}}\rightarrow {\frac {340}{47}}\rightarrow {\frac {170}{47}}\rightarrow {\frac {85}{47}}\rightarrow {\frac {151}{47}}.} 6760: 6164: 3076: 5226: 4107: 2168:
values may be ruled out. To state the argument more intuitively; we do not have to search for cycles that have less than 92 subsequences, where each subsequence consists of consecutive ups followed by consecutive downs.
5906: 5829: 5117: 216: 7548: 3548: 1631:(in the sense of logarithmic density) Collatz orbits are descending below any given function of the starting point, provided that this function diverges to infinity, no matter how slowly. Responding to this work, 1608:, almost every positive integer has a finite stopping time. In other words, almost every Collatz sequence reaches a point that is strictly below its initial value. The proof is based on the distribution of 1543:
on the length of the cycle, can be proven based on the value of the lowest term in the cycle. Therefore, computer searches to rule out cycles that have a small lowest term can strengthen these constraints.
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0, 1, 7, 2, 5, 8, 16, 3, 19, 6, 14, 9, 9, 17, 17, 4, 12, 20, 20, 7, 7, 15, 15, 10, 23, 10, 111, 18, 18, 18, 106, 5, 26, 13, 13, 21, 21, 21, 34, 8, 109, 8, 29, 16, 16, 16, 104, 11, 24, 24, ... (sequence
3371:. This implies that every number is uniquely identified by its parity sequence, and moreover that if there are multiple Hailstone cycles, then their corresponding parity cycles must be different. 6263: 1505:
Although the conjecture has not been proven, most mathematicians who have looked into the problem think the conjecture is true because experimental evidence and heuristic arguments support it.
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The problem is also known by several other names, including: Ulam's conjecture, the Hailstone problem, the Syracuse problem, Kakutani's problem, Hasse's algorithm, and the Collatz problem.
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integers: an 'even' such rational is divided by 2; an 'odd' such rational is multiplied by 3 and then 1 is added. A closely related fact is that the Collatz map extends to the ring of
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is generated by exactly one rational. Conversely, it is conjectured that every rational with an odd denominator has an eventually cyclic parity sequence (Periodicity Conjecture).
1489: 8545: 6605: 5160: 5013: 4961: 5545: 5454: 1980: 9290: 2923:, where each repetend is optionally rotated and then replicated up to a finite number of bits. It is only in binary that this occurs. Conjecturally, every binary string 5168: 8402: 5368: 6003: 590: 5641: 7792: 5446: 5419: 6246: 5325: 5276: 6660: 5018: 2380:{\displaystyle R(n)={\begin{cases}\{2n\}&{\text{if }}n\equiv 0,1,2,3,5\\\left\{2n,{\frac {n-1}{3}}\right\}&{\text{if }}n\equiv 4\end{cases}}{\pmod {6}}.} 1183:
1, 2, 3, 7, 15, 27, 255, 447, 639, 703, 1819, 4255, 4591, 9663, 20895, 26623, 31911, 60975, 77671, 113383, 138367, 159487, 270271, 665215, 704511, ... (sequence
6633: 6547: 6059: 5970: 5946: 5388: 5296: 4774:{\displaystyle T_{d}(x)={\begin{cases}{\frac {x}{2}}&{\text{if }}x\equiv 0{\pmod {2}},\\{\frac {3x+d}{2}}&{\text{if }}x\equiv 1{\pmod {2}}.\end{cases}}} 557: 537: 7458: 359:
Now form a sequence by performing this operation repeatedly, beginning with any positive integer, and taking the result at each step as the input at the next.
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So, instead of proving that all positive integers eventually lead to 1, we can try to prove that 1 leads backwards to all positive integers. For any integer
2641:{\displaystyle R(n)={\begin{cases}\{2n\}&{\text{if }}n\equiv 0,1\\\left\{2n,{\frac {2n-1}{3}}\right\}&{\text{if }}n\equiv 2\end{cases}}{\pmod {3}}.} 1812:{\displaystyle f(n)={\begin{cases}{\frac {n}{2}}&{\text{if }}n\equiv 0{\pmod {2}},\\{\frac {3n+1}{2}}&{\text{if }}n\equiv 1{\pmod {2}}.\end{cases}}} 831:{\displaystyle f(n)={\begin{cases}{\frac {n}{2}}&{\text{if }}n\equiv 0{\pmod {2}},\\{\frac {3n+1}{2}}&{\text{if }}n\equiv 1{\pmod {2}}.\end{cases}}} 9445: 4927:{\displaystyle T(x)={\begin{cases}{\frac {x}{2}}&{\text{if }}x\equiv 0{\pmod {2}}\\{\frac {3x+1}{2}}&{\text{if }}x\equiv 1{\pmod {2}}\end{cases}}} 2714:. Conjecturally, this inverse relation forms a tree except for a 1–2 loop (the inverse of the 1–2 loop of the function f(n) revised as indicated above). 9318:
by TomΓ‘s Oliveira e Silva continues to verify the Collatz conjecture (with fewer statistics than Eric Roosendaal's page but with further progress made).
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of a rational is not a multiple of 3, then all the iterates have the same denominator and the sequence of numerators can be obtained by applying the "
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for which such an inequality holds, so checking the Collatz conjecture for one starting value is as good as checking an entire congruence class. As
2140:. Simons (2005) used Steiner's method to prove that there is no 2-cycle. Simons and de Weger (2005) extended this proof up to 68-cycles; there is no 78: 52: 9150:
Proceedings of the 4th International Conference on Theory and Applications of Models of Computation, TAMC 2007, held in Shanghai, China in May 2007
3491:. This allows one to predict that certain forms of numbers will always lead to a smaller number after a certain number of iterations: for example, 6572:
Most of the points have orbits that diverge to infinity. Coloring these points based on how fast they diverge produces the image on the left, for
5916:, further investigated by Marc Chamberland. He showed that the conjecture does not hold for positive real numbers since there are infinitely many 5834: 5757: 3668:{\displaystyle f(n)={\begin{cases}{\frac {n}{2}}&{\text{if }}n\equiv 0\\{\frac {3n+1}{2}}&{\text{if }}n\equiv 1.\end{cases}}{\pmod {2}}} 3199:{\displaystyle f(n)={\begin{cases}{\frac {n}{2}}&{\text{if }}n\equiv 0\\{\frac {3n+1}{2}}&{\text{if }}n\equiv 1\end{cases}}{\pmod {2}}.} 9165: 8222: 838:
This definition yields smaller values for the stopping time and total stopping time without changing the overall dynamics of the process.
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These numbers are the lowest ones with the indicated step count, but not necessarily the only ones below the given limit. As an example,
7181:. Only an exponentially small fraction of the residues survive. For example, the only surviving residues mod 32 are 7, 15, 27, and 31. 6608: 6550: 879:, listed and graphed below, takes 111 steps (41 steps through odd numbers, in bold), climbing as high as 9232 before descending to 1. 8175: 8139: 8105: 8025: 7987: 4968: 1471:
values are shown. The first thick line towards the middle of the plot corresponds to the tip at 27, which reaches a maximum at 9232.
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1, 2, 3, 6, 7, 9, 18, 25, 27, 54, 73, 97, 129, 171, 231, 313, 327, 649, 703, 871, 1161, 2223, 2463, 2919, 3711, 6171, ... (sequence
350:{\displaystyle f(n)={\begin{cases}n/2&{\text{if }}n\equiv 0{\pmod {2}},\\3n+1&{\text{if }}n\equiv 1{\pmod {2}}.\end{cases}}} 2015: 8620: 7025:(0...31, 5) = {β€―0, 2, 1, 1, 2, 2, 2, 20, 1, 26, 1, 10, 4, 4, 13, 40, 2, 5, 17, 17, 2, 2, 20, 20, 8, 22, 8, 71, 26, 26, 80, 242β€―}. 69:
of small numbers under the Collatz map, skipping even numbers. The Collatz conjecture states that all paths eventually lead to 1.
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Odd values are listed in large bold. Each cycle is listed with its member of least absolute value (which is always odd) first.
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Ben-Amram, Amir M. (2015). "Mortality of iterated piecewise affine functions over the integers: Decidability and complexity".
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This process will eventually reach the number 1, regardless of which positive integer is chosen initially. That is, for each
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According to Lagarias (1985), p. 4, the name "Syracuse problem" was proposed by Hasse in the 1950s, during a visit to
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is an interpolation of the Collatz map to the complex plane. The reason for adding the extra term is to make all integers
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Collatz and related conjectures are often used when studying computation complexity. The connection is made through the
1649:, Krasikov and Lagarias showed that the number of integers in the interval that eventually reach 1 is at least equal to 9435: 6526: 2206: 2189: 1624: 1383:
The starting values having the smallest total stopping time with respect to their number of digits (in base 2) are the
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that ends with a '1' can be reached by a representation of this form (where we may add or delete leading '0's to 
1605: 9107: 8859:"Working in binary protects the repetends of 1/3: Comment on Colussi's 'The convergence classes of Collatz function'" 7012:, one can jump ahead 5 steps on each iteration by separating out the 5 least significant bits of a number and using 9440: 9297: 6807: 1528:
may be found when considering very large (or possibly immense) positive integers, as in the case of the disproven
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Numbers with a total stopping time longer than that of any smaller starting value form a sequence beginning with:
7019:(0...31, 5) = {β€―0, 3, 2, 2, 2, 2, 2, 4, 1, 4, 1, 3, 2, 2, 3, 4, 1, 2, 3, 3, 1, 1, 3, 3, 2, 3, 2, 4, 3, 3, 4, 5β€―}, 6769: 5917: 2944: 2839: 2197:
There is another approach to prove the conjecture, which considers the bottom-up method of growing the so-called
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Integers divisible by 3 cannot form a cycle, so these integers do not need to be checked as counter examples.
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However, such verifications may have other implications. Certain constraints on any non-trivial cycle, such as
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by David BaΕ™ina verifies Convergence of the Collatz conjecture for large values. (furthest progress so far)
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This computer evidence is still not rigorous proof that the conjecture is true for all starting values, as
713: 467:{\displaystyle a_{i}={\begin{cases}n&{\text{for }}i=0,\\f(a_{i-1})&{\text{for }}i>0\end{cases}}} 240: 9279: 8125: 7737: 6168: 3730:, and iteration of the tag operation halts on any word of length less than 2. (Adapted from De Mol.) 2210: 1637:
wrote that Tao "came away with one of the most significant results on the Collatz conjecture in decades".
207: 81:. The conjecture asks whether repeating two simple arithmetic operations will eventually transform every 8559: 8539: 5625:{\displaystyle g_{2}(n)={\begin{cases}0,&n{\text{ is even,}}\\1,&n{\text{ is odd,}}\end{cases}}} 5534:{\displaystyle g_{1}(n)={\begin{cases}1,&n{\text{ is even,}}\\0,&n{\text{ is odd,}}\end{cases}}} 1613: 7833: 9072: 6575: 5136: 4989: 4937: 4129:
has length 7 and four odd terms at indices 0, 2, 3, and 6. It is repeatedly generated by the fraction
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takes longer to reach 19, 58, 29, 88, 44, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1 .
9430: 8788: 8669: 8510: 6651: 4569:, that is, not partitionable into identical sub-cycles. As an illustration of this, the parity cycle 4556:{\displaystyle {\frac {3^{3}2^{1}+3^{2}2^{2}+3^{1}2^{5}+3^{0}2^{6}}{2^{7}-3^{4}}}={\frac {250}{47}}.} 1646: 90: 5576: 5485: 4272:{\displaystyle {\frac {3^{3}2^{0}+3^{2}2^{2}+3^{1}2^{3}+3^{0}2^{6}}{2^{7}-3^{4}}}={\frac {151}{47}}} 3733:
The Collatz conjecture equivalently states that this tag system, with an arbitrary finite string of
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axis represents the highest number reached during the chain to 1. This plot shows a restricted
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doesn't exist, we say that the stopping time or the total stopping time, respectively, is infinite.
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generated in bottom-up fashion. The graph includes all numbers with an orbit length of 21 or less.
9394: 9376: 8952: 8693: 8659: 8421: 8371: 8262: 8121: 8042: 7864: 7839: 7445: 5925: 2086: 1533: 203: 6557:. They conjectured that the latter is not the case, which would make all integer orbits finite. 8097: 7847: 6854:. The corresponding Julia set, shown on the right, consists of uncountably many curves, called 5743:{\displaystyle f(x)\triangleq {\frac {x}{2}}\cdot g_{1}(x)\,+\,{\frac {3x+1}{2}}\cdot g_{2}(x)} 9323: 9161: 9145: 8999: 8913: 8282: 8218: 8171: 8159: 8135: 8101: 7983: 7923: 6642: 5330: 5242:
of the orbit 10 β†’ 5 β†’ 8 β†’ 4 β†’ 2 β†’ 1 β†’ ... in an extension of the Collatz map to the real line.
5129:. Consequently, every infinite parity sequence occurs for exactly one 2-adic integer, so that 2902: 1820: 8131: 5975: 3978:, then the unique rational which generates immediately and periodically this parity cycle is 1556:
numbers in the sequence generated by the Collatz process, then each odd number is on average
562: 9402: 9221: 9194: 9153: 9053: 8989: 8944: 8903: 8870: 8837: 8796: 8677: 8639: 8591: 8518: 8461: 8411: 8363: 8313: 8272: 8228: 8202: 8181: 8089: 8034: 7361: 6039: 5921: 5913: 2940: 188: 139: 119: 86: 82: 66: 8810: 8757: 8689: 8605: 7770: 6755:{\displaystyle f(z)\triangleq {\frac {z}{2}}+{\frac {1}{4}}(2z+1)\left(1-e^{i\pi z}\right)} 5424: 5397: 3924:
The generalized Collatz conjecture is the assertion that every integer, under iteration by
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that halts. There is a 15 state Turing machine that halts if and only if a conjecture by
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extension of the Collatz process has two division steps for every multiplication step for
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in which each term is obtained from the previous term as follows: if the previous term is
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Histogram of total stopping times for the numbers 1 to 10. Total stopping time is on the
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Histogram of total stopping times for the numbers 1 to 10. Total stopping time is on the
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There are many other ways to define a complex interpolating function, such as using the
6159:{\displaystyle {\tfrac {1}{\pi }}\left({\tfrac {1}{2}}-\cos(\pi z)\right)\sin(\pi z)\,+} 4604:
are the only parity cycles generated by positive whole numbers (1 and 2, respectively).
3333:, depends on the parity. The parity sequence is the same as the sequence of operations. 9384: 9366: 8155: 7939: 7815: 7033: 6618: 6532: 6044: 5955: 5931: 5373: 5281: 4972: 3944:
When using the "shortcut" definition of the Collatz map, it is known that any periodic
2951:. The machine will perform the following three steps on any odd number until only one 2400: 1589: 542: 522: 105: 62: 8576: 8416: 8393: 3761:. These cycles are listed here, starting with the well-known cycle for positive  1572:
of the previous one. (More precisely, the geometric mean of the ratios of outcomes is
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there are 3 increases as 1 iterates to 2, 1, 2, 1, and finally to 2 so the result is
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said about the Collatz conjecture: "Mathematics may not be ready for such problems."
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trajectory point is greater than that of any smaller starting value are as follows:
9057: 8948: 8038: 7947: 7752:-complete. This hardness result holds even if one restricts the class of functions 6252:. Since this expression evaluates to zero for real integers, the extended function 2443:
except for the 1–2–4 loop (the inverse of the 4–2–1 loop of the unaltered function
1384: 9352: 8801: 8772: 5221:{\displaystyle Q\left(\mathbb {Z} ^{+}\right)\subset {\tfrac {1}{3}}\mathbb {Z} .} 1495:
The number of iterations it takes to get to one for the first 100 million numbers.
9157: 4102:{\displaystyle {\frac {3^{m-1}2^{k_{0}}+\cdots +3^{0}2^{k_{m-1}}}{2^{n}-3^{m}}}.} 3228:, then we can define the Collatz parity sequence (or parity vector) for a number 9311:
by Eric Roosendaal verifies the Collatz conjecture for larger and larger values.
7811: 5239: 3531:. Whether those smaller numbers continue to 1, however, depends on the value of 1620: 1540: 171: 17: 8367: 7448:
proved that a natural generalization of the Collatz problem is algorithmically
6553:, which implies that any integer is either eventually periodic or belongs to a 3427:
is how many increases were encountered during that sequence. For example, for
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without shortcut). If it can be shown that for all positive integers less than
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In this context, assuming the validity of the Collatz conjecture implies that
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The conjecture has been checked by computer for all starting values up to 2 β‰ˆ
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Michel, Pascal (1993). "Busy beaver competition and Collatz-like problems".
8596: 8332: 6612: 5949: 5901:{\displaystyle g_{2}(x)\triangleq \sin ^{2}\left({\tfrac {\pi }{2}}x\right)} 5824:{\displaystyle g_{1}(x)\triangleq \cos ^{2}\left({\tfrac {\pi }{2}}x\right)} 5247: 5235: 2800: 8994: 8971: 5112:{\displaystyle Q(x)=\sum _{k=0}^{\infty }\left(T^{k}(x)\mod 2\right)2^{k}.} 3941:, which contains the ring of rationals with odd denominators as a subring. 859:
without "shortcut", one gets the sequence 12, 6, 3, 10, 5, 16, 8, 4, 2, 1.
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Total stopping time of numbers up to 250, 1000, 4000, 20000, 100000, 500000
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function, where BB(n) is the maximum number of steps taken by any n state
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with respect to the 2-adic measure. Moreover, its dynamics is known to be
8354:
Barina, David (2020). "Convergence verification of the Collatz problem".
7799: 7543:{\displaystyle {g(n)=a_{i}n+b_{i}}{\text{ when }}{n\equiv i{\pmod {P}}},} 7439: 6889:
function from that section), break up the current number into two parts,
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above gives a way to speed up simulation of the sequence. To jump ahead
5126: 3928:, eventually falls into one of the four cycles above or the cycle 0 β†’ 0. 3451:
there is only 1 increase as 1 rises to 2 and falls to 1 so the result is
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is odd, one may instead use the "shortcut" form of the Collatz function:
9340: 9294: 179: 9225: 9198: 8425: 8277: 8250: 8077:. St Andrews University School of Mathematics and Statistics, Scotland. 8046: 6636: 6565: 2939:
Repeated applications of the Collatz function can be represented as an
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is the number of odd numbers encountered on the way. For example, if
2151:. Hercher extended the method further and proved that there exists no 2136:
Steiner (1977) proved that there is no 1-cycle other than the trivial
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The starting value having the largest total stopping time while being
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is associated to one of the above fractions. For instance, the cycle
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For this section, consider the shortcut form of the Collatz function
660:
The Collatz conjecture asserts that the total stopping time of every
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Are computers ready to solve this notoriously unwieldy math problem?
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The Collatz conjecture is equivalent to the statement that, for all
7165:
which is not a counterexample to the Collatz conjecture, there is a
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Proceedings of the 7th Manitoba Conference on Numerical Mathematics
8267: 8251:"Almost all orbits of the Collatz map attain almost bounded values" 6901:(the rest of the bits as an integer). The result of jumping ahead 6641: 6559: 5234: 2181: 2008:
without shortcut). In fact, Eliahou (1993) proved that the period
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Numbers from 1 to 9999 and their corresponding total stopping time
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is always an integer. The standard Collatz function is given by
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and storage to speed up the resulting calculation by a factor of
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which exhibit different dynamics. In this case, for instance, if
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In this part, consider the shortcut form of the Collatz function
6038:. Moreover, the set of unbounded orbits is conjectured to be of 9276: 8891: 8481: 8479: 8477: 49:
With enough repetition, do all positive integers converge to 1?
9040:
Letherman, Simon; Schleicher, Dierk; Wood, Reg (1999). "The (3
7117:. For instance, the first counterexample must be odd because 2948: 2879:
is a finite and contiguous extract from the representation of
1982:
the Collatz sequences reach 1, then this bound would raise to
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Steiner, R. P. (1977). "A theorem on the syracuse problem".
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An equivalent formulation of the Collatz conjecture is that
3347:, it can be shown that the parity sequences for two numbers 2997:
s (that is, repeatedly divide by 2 until the result is odd).
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Directed graph showing the orbits of the first 1000 numbers.
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function. A simple way to do this is to pick two functions
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Add this to the original number by binary addition (giving
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The same plot as the previous one but on log scale, so all
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Chamberland, Marc (1996). "A continuous extension of the 3
8450:+ 1 problem: new lower bounds on nontrivial cycle lengths" 6064:
Letherman, Schleicher, and Wood extended the study to the
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For a one-to-one correspondence, a parity cycle should be
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The length of a non-trivial cycle is known to be at least
8621:"Mathematician Proves Huge Result on 'Dangerous' Problem" 7173:
increases, the search only needs to check those residues
7109:, then the first counterexample, if it exists, cannot be 2466:
is replaced by the common substitute "shortcut" relation
8344:(Note: "Delay records" are total stopping time records.) 6897:
least significant bits, interpreted as an integer), and
2488:, the Collatz graph is defined by the inverse relation, 9304:
that verifies the Collatz conjecture for larger values.
9146:"The undecidability of the generalized Collatz problem" 9131:
Proc. 1972 Number Theory Conf., Univ. Colorado, Boulder
9077:+ 1 problem by means of the COMETA grid infrastructure" 6607:. The inner black regions and the outer region are the 1483:
The tree of all the numbers having fewer than 20 steps.
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to odd numbers. Now suppose that for some odd number
664:
is finite. It is also equivalent to saying that every
8648: + 1 problem using difference inequalities" 8300:
Leavens, Gary T.; Vermeulen, Mike (December 1992). "3
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centered at the origin, with real parts from -5 to 5.
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from the original on 2021-12-11 – via YouTube.
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from the original on 2021-12-11 – via YouTube.
9129:
Conway, John H. (1972). "Unpredictable iterations".
9044: + 1)-problem and holomorphic dynamics". 8970:Bernstein, Daniel J.; Lagarias, Jeffrey C. (1996). 2963:to the (right) end of the number in binary (giving 2162:. As exhaustive computer searches continue, larger 1623:improved this result by showing, using logarithmic 8577:"A stopping time problem on the positive integers" 7786: 7542: 7455:Specifically, he considered functions of the form 6846: 6796: 6754: 6627: 6599: 6541: 6514: 6240: 6211: 6158: 6053: 6030: 5997: 5964: 5940: 5900: 5823: 5742: 5624: 5533: 5440: 5413: 5382: 5362: 5319: 5290: 5270: 5220: 5154: 5111: 5007: 4955: 4926: 4773: 4555: 4392: 4271: 4101: 3667: 3198: 2640: 2379: 2051: 1974: 1811: 830: 584: 551: 531: 466: 349: 8933:"Embedding the 3x+1 Conjecture in a 3x+d Context" 8892:"The set of rational cycles for the 3x+1 problem" 8709: 8707: 8439: 8437: 8435: 8197: 8195: 8014: 8012: 8010: 8008: 8006: 8004: 8002: 5635:and use them as switches for our desired values: 187:Consider the following operation on an arbitrary 9148:. In Cai, J.-Y.; Cooper, S. B.; Zhu, H. (eds.). 8570: 8568: 8544:: CS1 maint: bot: original URL status unknown ( 8403:Proceedings of the American Mathematical Society 8387: 8385: 7978:Maddux, Cleborne D.; Johnson, D. Lamont (1997). 7246:of positive odd integers into itself, for which 7177:that are not eliminated by lower values of  3006:The starting number 7 is written in base two as 2935:As an abstract machine that computes in base two 7767:in a simplified version of this form, with all 7697:Closer to the Collatz problem is the following 6639:pattern, sometimes called a "Collatz fractal". 6549:. With this, they show that no integer is in a 4622: " generalization of the Collatz function 2439:. Conjecturally, this inverse relation forms a 2122:-cycle is a cycle that can be partitioned into 9411:(short video). Veritasium – via YouTube. 7586:are rational numbers which are so chosen that 7276:Some properties of the Syracuse function are: 3543:For the Collatz function in the shortcut form 9108:"The Long Search for Collatz Counterexamples" 8931:Belaga, Edward G.; Mignotte, Maurice (1998). 8826:"The convergence classes of Collatz function" 8306:Computers & Mathematics with Applications 6847:{\displaystyle f(z)\approx z+{\tfrac {1}{4}}} 2448: 2052:{\displaystyle p=301994a+17087915b+85137581c} 8: 8096:. Oxford: Oxford University Press. pp.  5250:by choosing any function which evaluates to 3932:Iterating on rationals with odd denominators 2527: 2518: 2251: 2242: 198:If the number is odd, triple it and add one. 9084:Grid Open Days at the University of Palermo 6797:{\displaystyle \operatorname {Im} (z)\gg 1} 6646:Julia set of the exponential interpolation. 3737:as the initial word, eventually halts (see 3677:Hailstone sequences can be computed by the 1230:less than 1000 is 871, which has 178 steps, 9408:The simplest math problem no one can solve 9021: + 1 problem to the real line". 8773:"On the nonexistence of 2-cycles for the 3 8527:. Archived from the original on 2022-03-18 8488:"Theoretical and computational bounds for 6281: 4279:as the latter leads to the rational cycle 1521:. All values tested so far converge to 1. 1395:times to reach 1, and is never increased. 1233:less than 10 is 6171, which has 261 steps, 8993: 8907: 8874: 8841: 8800: 8663: 8595: 8522: 8465: 8415: 8276: 8266: 7778: 7772: 7520: 7510: 7505: 7498: 7482: 7462: 7460: 6877: 6832: 6809: 6771: 6735: 6692: 6679: 6662: 6620: 6577: 6534: 6487: 6414: 6399: 6390: 6372: 6358: 6333: 6312: 6298: 6284: 6262: 6260: 6224: 6188: 6170: 6152: 6096: 6079: 6077: 6046: 6021: 6010: 5988: 5977: 5957: 5933: 5878: 5864: 5842: 5836: 5801: 5787: 5765: 5759: 5725: 5697: 5696: 5692: 5677: 5660: 5643: 5610: 5590: 5571: 5553: 5547: 5519: 5499: 5480: 5462: 5456: 5432: 5426: 5405: 5399: 5375: 5352: 5332: 5303: 5283: 5260: 5255: 5211: 5210: 5198: 5185: 5181: 5180: 5170: 5146: 5142: 5141: 5138: 5100: 5087: 5086: 5067: 5052: 5041: 5020: 4999: 4995: 4994: 4991: 4947: 4943: 4942: 4939: 4901: 4887: 4864: 4844: 4830: 4818: 4810: 4793: 4745: 4731: 4708: 4685: 4671: 4659: 4651: 4633: 4627: 4540: 4528: 4515: 4503: 4493: 4480: 4470: 4457: 4447: 4434: 4424: 4417: 4415: 4377: 4364: 4351: 4338: 4325: 4312: 4299: 4286: 4284: 4259: 4247: 4234: 4222: 4212: 4199: 4189: 4176: 4166: 4153: 4143: 4136: 4134: 4087: 4074: 4054: 4049: 4039: 4018: 4013: 3997: 3990: 3988: 3945: 3649: 3628: 3605: 3587: 3575: 3567: 3550: 3177: 3156: 3133: 3115: 3103: 3095: 3078: 2619: 2598: 2570: 2532: 2510: 2493: 2358: 2337: 2312: 2256: 2234: 2217: 2017: 1966: 1954: 1783: 1769: 1746: 1723: 1709: 1697: 1689: 1672: 1609: 1227:less than 100 is 97, which has 118 steps, 802: 788: 765: 742: 728: 716: 708: 691: 570: 564: 544: 524: 443: 426: 395: 382: 373: 367: 321: 307: 270: 256: 246: 235: 218: 45:For odd numbers, multiply by 3 and add 1. 8073:O'Connor, J.J.; Robertson, E.F. (2006). 7982:. New York: Haworth Press. p. 160. 3770: 2012:of any non-trivial cycle is of the form 1440:values produce intermediates as high as 195:If the number is even, divide it by two. 9144:Kurtz, Stuart A.; Simon, Janos (2007). 7970: 7881: 6611:, and the boundary between them is the 6068:. They used Chamberland's function for 6031:{\displaystyle (1.1925...;\,2.1386...)} 5246:The Collatz map can be extended to the 2838:can be written as the concatenation of 1915:of period 2, called the trivial cycle. 1402: 101:, but no general proof has been found. 53:(more unsolved problems in mathematics) 9240:"Hardness of busy beaver value BB(15)" 9023:Dynam. Contin. Discrete Impuls Systems 8537: 8244: 8242: 8023:+ 1 problem and its generalizations". 6955:can be precalculated for all possible 3010:. The resulting Collatz sequence is: 1224:less than 10 is 9, which has 19 steps, 27:Open problem on 3x+1 and x/2 functions 8619:Hartnett, Kevin (December 11, 2019). 5390:is an odd integer. This is called an 3718:In this system, the positive integer 3487:; it depends only on the behavior of 1428:axis represents starting number, the 175:Iteration time for inputs of 2 to 10. 112:in a cloud), or as wondrous numbers. 7: 9314:Another ongoing volunteer computing 8857:Hew, Patrick Chisan (7 March 2016). 7794:equal to zero, are formalized in an 7690:is undecidable, by representing the 6212:{\displaystyle h(z)\sin ^{2}(\pi z)} 5231:Iterating on real or complex numbers 4577:are associated to the same fraction 3980: 2819:times yields the number 1 (that is, 2173:Other formulations of the conjecture 1848:of distinct positive integers where 104:It is named after the mathematician 9372:Uncrackable? The Collatz conjecture 9073:"Looking for class records in the 3 8824:Colussi, Livio (9 September 2011). 8019:Lagarias, Jeffrey C. (1985). "The 3 7528: 6885:steps on each iteration (using the 4909: 4902: 4852: 4845: 4753: 4746: 4693: 4686: 3657: 3212:is the parity of a number, that is 3185: 2627: 2366: 1791: 1784: 1731: 1724: 810: 803: 750: 743: 329: 322: 278: 271: 9446:Unsolved problems in number theory 8164:Unsolved Problems in Number Theory 8130:. New York: Basic Books. pp.  5370:(for the "shortcut" version) when 5298:is an even integer, and to either 5053: 1340:, which has 1348 steps. (sequence 25: 8486:Simons, J.; de Weger, B. (2005). 8417:10.1090/S0002-9939-1981-0603593-2 8026:The American Mathematical Monthly 7659:. Conway proved that the problem 7138:; and it must be 3 mod 4 because 3955:and includes odd numbers exactly 7832: 7709:, does the sequence of iterates 7671:, does the sequence of iterates 6600:{\displaystyle h(z)\triangleq 0} 5155:{\displaystyle \mathbb {Z} _{2}} 5008:{\displaystyle \mathbb {Z} _{2}} 4956:{\displaystyle \mathbb {Z} _{2}} 1488: 1476: 1460: 1417: 1405: 79:unsolved problems in mathematics 9390:Uncrackable? Collatz conjecture 9307:An ongoing volunteer computing 8981:Canadian Journal of Mathematics 7870:Residue-class-wise affine group 7521: 5082: 3650: 3483:is independent of the value of 3178: 2620: 2359: 34:Unsolved problem in mathematics 9393:(extra footage). Numberphile. 9358:Wolfram Demonstrations Project 9214:Archive for Mathematical Logic 9058:10.1080/10586458.1999.10504402 8949:10.1080/10586458.1998.10504364 8088:Pickover, Clifford A. (2001). 8039:10.1080/00029890.1985.11971528 7532: 7522: 7472: 7466: 6978:is the result of applying the 6820: 6814: 6785: 6779: 6717: 6702: 6673: 6667: 6588: 6582: 6505: 6496: 6480: 6474: 6465: 6456: 6442: 6433: 6275: 6269: 6235: 6229: 6206: 6197: 6181: 6175: 6149: 6140: 6126: 6117: 6025: 6012: 5992: 5979: 5854: 5848: 5777: 5771: 5737: 5731: 5689: 5683: 5654: 5648: 5565: 5559: 5474: 5468: 5349: 5334: 5079: 5073: 5031: 5025: 4913: 4903: 4856: 4846: 4804: 4798: 4757: 4747: 4697: 4687: 4645: 4639: 4593:when reduced to lowest terms. 4374: 4361: 4348: 4335: 4322: 4309: 4296: 4125:For example, the parity cycle 3722:is represented by a string of 3661: 3651: 3561: 3555: 3411:is the result of applying the 3291:Which operation is performed, 3189: 3179: 3089: 3083: 2631: 2621: 2504: 2498: 2370: 2360: 2228: 2222: 2085:. This result is based on the 1975:{\displaystyle 3\times 2^{69}} 1795: 1785: 1735: 1725: 1683: 1677: 814: 804: 754: 744: 702: 696: 438: 419: 333: 323: 282: 272: 229: 223: 42:For even numbers, divide by 2; 1: 8802:10.1090/s0025-5718-04-01728-4 8356:The Journal of Supercomputing 8215:American Mathematical Society 8207:The Ultimate Challenge: The 3 7796:esoteric programming language 4967:, where it is continuous and 3951:If a parity cycle has length 3479:. The power of 3 multiplying 3471:rises and the result will be 9405:(featuring) (30 July 2021). 9375:(short video). Numberphile. 9158:10.1007/978-3-540-72504-6_49 8863:Theoretical Computer Science 8830:Theoretical Computer Science 8731:Journal of Integer Sequences 8467:10.1016/0012-365X(93)90052-U 8318:10.1016/0898-1221(92)90034-F 7328:In more generality: For all 6654:instead of sine and cosine: 5133:trajectories are acyclic in 4934:is well-defined on the ring 4410:is produced by the fraction 3904:β†’ βˆ’272 β†’ βˆ’136 β†’ βˆ’68 β†’ βˆ’34 β†’ 3747:Extensions to larger domains 846:For instance, starting with 671:has a finite stopping time. 9096:Lagarias (1985), Theorem D. 7806:In computational complexity 7434:Undecidable generalizations 7362:function iteration notation 7161:. For each starting value 3527:after four applications of 2803:). The resulting function 2717:Alternatively, replace the 2186:The first 21 levels of the 2071:are non-negative integers, 1655:for all sufficiently large 516:The Collatz conjecture is: 9462: 8890:Lagarias, Jeffrey (1990). 8558:Lagarias (1985), section " 8368:10.1007/s11227-020-03368-x 7437: 7412:, there exists an integer 5928:to infinity. The function 4402:Any cyclic permutation of 3507:after two applications of 2815:, applying this operation 2451:section of this article). 1552:If one considers only the 1175:The starting values whose 1080:, 9232, 4616, 2308, 1154, 853:and applying the function 627:. Similarly, the smallest 77:is one of the most famous 9071:Scollo, Giuseppe (2007). 8876:10.1016/j.tcs.2015.12.033 8843:10.1016/j.tcs.2011.05.056 8398: + 1 algorithm" 8160:""E16: The 3x+1 problem"" 6072:and added the extra term 3752:Iterating on all integers 1596:2-adic starting values.) 1548:A probabilistic heuristic 9046:Experimental Mathematics 8937:Experimental Mathematics 8771:Simons, John L. (2005). 8444:Eliahou, Shalom (1993). 8392:Garner, Lynn E. (1981). 8255:Forum of Mathematics, Pi 7888:It is also known as the 7196:is an odd integer, then 5363:{\displaystyle (3x+1)/2} 3355:will agree in the first 2897:. The representation of 2449:Statement of the problem 1911:The only known cycle is 1367:has 1132 steps, as does 649:. If one of the indexes 127:Statement of the problem 9106:Clay, Oliver Keatinge. 8597:10.4064/aa-30-3-241-252 8496: + 1 problem" 6070:complex sine and cosine 5998:{\displaystyle (1;\,2)} 4607:If the odd denominator 3743:for a worked example). 2209:defined by the inverse 1324:, which has 1228 steps, 1308:, which has 1132 steps, 1122:, 160, 80, 40, 20, 10, 585:{\displaystyle a_{i}=1} 163:axis, frequency on the 147:axis, frequency on the 9293:) volunteer computing 8995:10.4153/CJM-1996-060-x 8716:"There are no Collatz 8304:+ 1 search programs". 8122:Hofstadter, Douglas R. 7788: 7756:by fixing the modulus 7740:; specifically, it is 7738:arithmetical hierarchy 7699:universally quantified 7544: 7057:. If, for some given 6848: 6798: 6756: 6647: 6629: 6601: 6569: 6543: 6516: 6242: 6213: 6160: 6055: 6032: 5999: 5966: 5942: 5912:of this map lead to a 5902: 5825: 5744: 5626: 5535: 5442: 5415: 5384: 5364: 5321: 5292: 5272: 5243: 5222: 5156: 5113: 5057: 5009: 4957: 4928: 4775: 4557: 4394: 4273: 4103: 3777:Odd-value cycle length 3681:with production rules 3669: 3367:are equivalent modulo 3200: 2642: 2381: 2194: 2053: 1976: 1813: 1292:, which has 986 steps, 1279:, which has 949 steps, 1266:, which has 685 steps, 1253:, which has 524 steps, 1243:, which has 350 steps, 1154: 1098:, 976, 488, 244, 122, 832: 586: 553: 533: 468: 351: 184: 176: 168: 152: 136: 70: 8909:10.4064/aa-56-1-33-53 8575:Terras, Riho (1976). 8560:A heuristic argument" 8249:Tao, Terence (2022). 7980:Logo: A Retrospective 7789: 7787:{\displaystyle b_{i}} 7545: 6849: 6799: 6757: 6645: 6630: 6602: 6563: 6544: 6517: 6243: 6214: 6161: 6056: 6033: 6000: 5967: 5943: 5903: 5826: 5745: 5627: 5536: 5443: 5441:{\displaystyle g_{2}} 5416: 5414:{\displaystyle g_{1}} 5385: 5365: 5322: 5293: 5273: 5238: 5223: 5157: 5114: 5037: 5010: 4958: 4929: 4776: 4558: 4395: 4274: 4104: 3670: 3396:will give the result 3359:terms if and only if 3201: 2643: 2382: 2185: 2054: 1977: 1814: 1614:central limit theorem 1509:Experimental evidence 1153: 833: 587: 554: 534: 469: 352: 206:notation, define the 182: 174: 158: 142: 134: 87:sequences of integers 61: 9152:. pp. 542–553. 8737:(3): Article 23.3.5. 8714:Hercher, C. (2023). 8640:Lagarias, Jeffrey C. 8454:Discrete Mathematics 8333:"3x+1 delay records" 8203:Lagarias, Jeffrey C. 7771: 7459: 7048:Modular restrictions 6878:As a parity sequence 6808: 6770: 6661: 6619: 6576: 6533: 6259: 6241:{\displaystyle h(z)} 6223: 6169: 6076: 6045: 6009: 5976: 5956: 5932: 5835: 5758: 5642: 5546: 5455: 5425: 5398: 5374: 5331: 5320:{\displaystyle 3x+1} 5302: 5282: 5254: 5169: 5137: 5019: 4990: 4938: 4792: 4626: 4414: 4283: 4133: 3987: 3549: 3382:times to the number 3336:Using this form for 3077: 3069:As a parity sequence 2993:Remove all trailing 2901:therefore holds the 2492: 2216: 2016: 1953: 1671: 1647:computer-aided proof 1501:Supporting arguments 1197:Number of steps for 1056:, 7288, 3644, 1822, 690: 563: 543: 523: 366: 217: 85:into 1. It concerns 9436:Arithmetic dynamics 9274:volunteer computing 8793:2005MaCom..74.1565S 8674:2003AcAri.109..237K 8515:2005AcAri.117...51S 8127:GΓΆdel, Escher, Bach 8061:Syracuse University 7956:Syracuse University 7936:Thwaites conjecture 7860:Arithmetic dynamics 7042:space–time tradeoff 6871:Time–space tradeoff 6652:complex exponential 5754:One such choice is 5271:{\displaystyle x/2} 3467:then there will be 643:total stopping time 9387:(August 9, 2016). 9324:Weisstein, Eric W. 9300:2017-12-04 at the 9282:2021-08-30 at the 9226:10.1007/BF01409968 9199:10.3233/COM-150032 8976:+ 1 conjugacy map" 8752:. pp. 553–9. 8331:Roosendaal, Eric. 8278:10.1017/fmp.2022.8 8170:. pp. 330–6. 8092:Wonders of Numbers 7928:Kakutani's problem 7865:Modular arithmetic 7840:Mathematics portal 7784: 7540: 7446:John Horton Conway 6844: 6842: 6794: 6752: 6648: 6625: 6597: 6570: 6539: 6512: 6510: 6238: 6209: 6156: 6106: 6089: 6051: 6028: 5995: 5962: 5938: 5898: 5888: 5821: 5811: 5740: 5622: 5617: 5531: 5526: 5438: 5411: 5380: 5360: 5317: 5288: 5268: 5244: 5218: 5208: 5152: 5109: 5005: 4969:measure-preserving 4953: 4924: 4919: 4771: 4766: 4573:and its sub-cycle 4553: 4390: 4269: 4099: 3780:Full cycle length 3665: 3644: 3196: 3172: 2638: 2614: 2454:When the relation 2377: 2353: 2195: 2087:continued fraction 2049: 1972: 1809: 1804: 1534:Mertens conjecture 1155: 990:, 1336, 668, 334, 828: 823: 582: 549: 529: 464: 459: 347: 342: 204:modular arithmetic 185: 177: 169: 153: 137: 75:Collatz conjecture 71: 9441:Integer sequences 9369:(8 August 2016). 9351:Nochella, Jesse. 9327:"Collatz Problem" 9256:Matthews, Keith. 9167:978-3-540-72503-9 9133:. pp. 49–52. 8836:(39): 5409–5419. 8682:10.4064/aa109-3-4 8644:"Bounds for the 3 8524:10.4064/aa117-1-3 8394:"On the Collatz 3 8224:978-0-8218-4940-8 7944:Hasse's algorithm 7508: 7236:Syracuse function 7188:Syracuse function 7065:, the inequality 6841: 6700: 6687: 6628:{\displaystyle f} 6542:{\displaystyle f} 6422: 6407: 6380: 6352: 6320: 6292: 6105: 6088: 6054:{\displaystyle 0} 5965:{\displaystyle 2} 5952:cycles of period 5941:{\displaystyle f} 5887: 5810: 5716: 5668: 5613: 5593: 5522: 5502: 5383:{\displaystyle x} 5291:{\displaystyle x} 5207: 4890: 4883: 4833: 4826: 4734: 4727: 4674: 4667: 4571:(1 1 0 0 1 1 0 0) 4548: 4535: 4385: 4372: 4359: 4346: 4333: 4320: 4307: 4294: 4267: 4254: 4123: 4122: 4094: 3959:times at indices 3922: 3921: 3631: 3624: 3590: 3583: 3159: 3152: 3118: 3111: 2601: 2589: 2535: 2340: 2328: 2259: 1772: 1765: 1712: 1705: 872:The sequence for 791: 784: 731: 724: 682:is even whenever 552:{\displaystyle i} 532:{\displaystyle n} 446: 398: 310: 259: 16:(Redirected from 9453: 9412: 9403:Alex Kontorovich 9398: 9380: 9362: 9337: 9336: 9269: 9265: 9263: 9244: 9243: 9236: 9230: 9229: 9209: 9203: 9202: 9182: 9176: 9171: 9141: 9135: 9134: 9126: 9120: 9119: 9117: 9115: 9103: 9097: 9094: 9088: 9087: 9081: 9068: 9062: 9061: 9037: 9031: 9030: 9014: 9008: 9007: 8997: 8988:(6): 1154–1169. 8967: 8961: 8960: 8928: 8922: 8921: 8911: 8896:Acta Arithmetica 8887: 8881: 8880: 8878: 8854: 8848: 8847: 8845: 8821: 8815: 8814: 8804: 8768: 8762: 8761: 8745: 8739: 8738: 8728: 8711: 8702: 8701: 8667: 8652:Acta Arithmetica 8638:Krasikov, Ilia; 8635: 8629: 8628: 8616: 8610: 8609: 8599: 8584:Acta Arithmetica 8581: 8572: 8563: 8556: 8550: 8549: 8543: 8535: 8533: 8532: 8526: 8503:Acta Arithmetica 8500: 8492:-cycles of the 3 8483: 8472: 8471: 8469: 8441: 8430: 8429: 8419: 8389: 8380: 8379: 8362:(3): 2681–2688. 8351: 8345: 8343: 8341: 8339: 8328: 8322: 8321: 8297: 8291: 8290: 8280: 8270: 8246: 8237: 8236: 8199: 8190: 8189: 8166:(3rd ed.). 8152: 8146: 8145: 8118: 8112: 8111: 8095: 8085: 8079: 8078: 8075:"Lothar Collatz" 8070: 8064: 8057: 8051: 8050: 8016: 7997: 7996: 7975: 7959: 7952:Syracuse problem 7911: 7896: 7886: 7854: 7842: 7837: 7836: 7793: 7791: 7790: 7785: 7783: 7782: 7766: 7759: 7755: 7751: 7750: 7749: 7730: 7723: 7719: 7708: 7685: 7681: 7670: 7666: 7658: 7648: 7638: 7628: 7627: 7625: 7624: 7621: 7618: 7603: 7596: 7585: 7549: 7547: 7546: 7541: 7536: 7535: 7509: 7507: when  7506: 7504: 7503: 7502: 7487: 7486: 7429: 7418: 7411: 7407: 7400: 7399: 7397: 7396: 7393: 7390: 7370: 7359: 7353: 7338: 7334: 7324: 7308: 7289: 7268: 7262: 7261: 7245: 7241: 7238:is the function 7233: 7226: 7225: 7217: 7216: 7203: 7195: 7180: 7176: 7172: 7168: 7164: 7160: 7152: 7137: 7130: 7116: 7112: 7108: 7101: 7064: 7060: 7056: 7039: 7032: 7024: 7018: 7011: 7004: 6989: 6985: 6981: 6977: 6962: 6958: 6954: 6950: 6946: 6938: 6904: 6900: 6896: 6892: 6888: 6884: 6853: 6851: 6850: 6845: 6843: 6834: 6803: 6801: 6800: 6795: 6761: 6759: 6758: 6753: 6751: 6747: 6746: 6745: 6701: 6693: 6688: 6680: 6635:, which forms a 6634: 6632: 6631: 6626: 6609:Fatou components 6606: 6604: 6603: 6598: 6555:wandering domain 6548: 6546: 6545: 6540: 6521: 6519: 6518: 6513: 6511: 6492: 6491: 6449: 6445: 6423: 6415: 6408: 6400: 6397: 6389: 6385: 6381: 6373: 6363: 6362: 6353: 6348: 6334: 6329: 6325: 6321: 6313: 6303: 6302: 6293: 6285: 6247: 6245: 6244: 6239: 6218: 6216: 6215: 6210: 6193: 6192: 6165: 6163: 6162: 6157: 6133: 6129: 6107: 6098: 6090: 6081: 6060: 6058: 6057: 6052: 6037: 6035: 6034: 6029: 6004: 6002: 6001: 5996: 5971: 5969: 5968: 5963: 5947: 5945: 5944: 5939: 5914:dynamical system 5907: 5905: 5904: 5899: 5897: 5893: 5889: 5880: 5869: 5868: 5847: 5846: 5830: 5828: 5827: 5822: 5820: 5816: 5812: 5803: 5792: 5791: 5770: 5769: 5749: 5747: 5746: 5741: 5730: 5729: 5717: 5712: 5698: 5682: 5681: 5669: 5661: 5631: 5629: 5628: 5623: 5621: 5620: 5614: 5611: 5594: 5591: 5558: 5557: 5540: 5538: 5537: 5532: 5530: 5529: 5523: 5520: 5503: 5500: 5467: 5466: 5447: 5445: 5444: 5439: 5437: 5436: 5420: 5418: 5417: 5412: 5410: 5409: 5389: 5387: 5386: 5381: 5369: 5367: 5366: 5361: 5356: 5326: 5324: 5323: 5318: 5297: 5295: 5294: 5289: 5277: 5275: 5274: 5269: 5264: 5227: 5225: 5224: 5219: 5214: 5209: 5200: 5194: 5190: 5189: 5184: 5161: 5159: 5158: 5153: 5151: 5150: 5145: 5124: 5118: 5116: 5115: 5110: 5105: 5104: 5095: 5091: 5072: 5071: 5056: 5051: 5014: 5012: 5011: 5006: 5004: 5003: 4998: 4985: 4962: 4960: 4959: 4954: 4952: 4951: 4946: 4933: 4931: 4930: 4925: 4923: 4922: 4916: 4891: 4888: 4884: 4879: 4865: 4859: 4834: 4831: 4827: 4819: 4784:2-adic extension 4780: 4778: 4777: 4772: 4770: 4769: 4760: 4735: 4732: 4728: 4723: 4709: 4700: 4675: 4672: 4668: 4660: 4638: 4637: 4621: 4610: 4603: 4599: 4592: 4590: 4589: 4586: 4583: 4576: 4572: 4562: 4560: 4559: 4554: 4549: 4541: 4536: 4534: 4533: 4532: 4520: 4519: 4509: 4508: 4507: 4498: 4497: 4485: 4484: 4475: 4474: 4462: 4461: 4452: 4451: 4439: 4438: 4429: 4428: 4418: 4409: 4405: 4399: 4397: 4396: 4391: 4386: 4378: 4373: 4365: 4360: 4352: 4347: 4339: 4334: 4326: 4321: 4313: 4308: 4300: 4295: 4287: 4278: 4276: 4275: 4270: 4268: 4260: 4255: 4253: 4252: 4251: 4239: 4238: 4228: 4227: 4226: 4217: 4216: 4204: 4203: 4194: 4193: 4181: 4180: 4171: 4170: 4158: 4157: 4148: 4147: 4137: 4128: 4117: 4108: 4106: 4105: 4100: 4095: 4093: 4092: 4091: 4079: 4078: 4068: 4067: 4066: 4065: 4064: 4044: 4043: 4025: 4024: 4023: 4022: 4008: 4007: 3991: 3981: 3977: 3958: 3954: 3927: 3771: 3764: 3760: 3736: 3729: 3725: 3721: 3713: 3703: 3693: 3674: 3672: 3671: 3666: 3664: 3648: 3647: 3632: 3629: 3625: 3620: 3606: 3591: 3588: 3584: 3576: 3534: 3530: 3526: 3518: 3510: 3506: 3498: 3490: 3486: 3482: 3478: 3470: 3466: 3462: 3458: 3450: 3442: 3434: 3426: 3422: 3418: 3414: 3410: 3406: 3395: 3381: 3377: 3370: 3366: 3362: 3358: 3354: 3350: 3346: 3332: 3331: 3329: 3328: 3325: 3322: 3312: 3311: 3309: 3308: 3305: 3302: 3287: 3261: 3248: 3231: 3227: 3219: 3211: 3205: 3203: 3202: 3197: 3192: 3176: 3175: 3160: 3157: 3153: 3148: 3134: 3119: 3116: 3112: 3104: 3009: 2996: 2989: 2970: 2962: 2954: 2941:abstract machine 2930: 2926: 2922: 2921: 2919: 2918: 2915: 2912: 2900: 2896: 2895: 2893: 2892: 2889: 2886: 2878: 2867: 2837: 2829: 2818: 2814: 2806: 2798: 2797: 2785: 2783: 2771: 2765: 2757: 2756: 2754: 2753: 2751: 2740: 2737: 2736: 2724: 2713: 2706: 2704: 2702: 2701: 2698: 2695: 2684:. Equivalently, 2683: 2681: 2679: 2678: 2675: 2672: 2660: 2653: 2650:For any integer 2647: 2645: 2644: 2639: 2634: 2618: 2617: 2602: 2599: 2595: 2591: 2590: 2585: 2571: 2536: 2533: 2487: 2486: 2484: 2483: 2480: 2477: 2465: 2462:of the function 2461: 2446: 2438: 2431: 2429: 2427: 2426: 2423: 2420: 2410:. Equivalently, 2409: 2399: 2392: 2386: 2384: 2383: 2378: 2373: 2357: 2356: 2341: 2338: 2334: 2330: 2329: 2324: 2313: 2260: 2257: 2167: 2161: 2150: 2143: 2139: 2127: 2121: 2113: 2106: 2105: 2103: 2102: 2099: 2096: 2084: 2077: 2070: 2066: 2062: 2058: 2056: 2055: 2050: 2011: 2007: 2006: 2003: 2000: 1994: 1993: 1990: 1987: 1981: 1979: 1978: 1973: 1971: 1970: 1948: 1947: 1944: 1941: 1935: 1934: 1931: 1928: 1914: 1907: 1887: 1867: 1847: 1818: 1816: 1815: 1810: 1808: 1807: 1798: 1773: 1770: 1766: 1761: 1747: 1738: 1713: 1710: 1706: 1698: 1658: 1654: 1587: 1585: 1584: 1581: 1578: 1571: 1569: 1568: 1565: 1562: 1530:PΓ³lya conjecture 1520: 1518: 1492: 1480: 1470: 1464: 1454: 1447: 1445: 1439: 1435: 1431: 1427: 1421: 1409: 1394: 1390: 1379: 1378: 1375: 1372: 1366: 1365: 1362: 1359: 1345: 1339: 1338: 1335: 1332: 1327:less than 10 is 1323: 1322: 1319: 1316: 1311:less than 10 is 1307: 1306: 1303: 1300: 1295:less than 10 is 1291: 1290: 1287: 1282:less than 10 is 1278: 1277: 1274: 1269:less than 10 is 1265: 1264: 1261: 1256:less than 10 is 1252: 1251: 1246:less than 10 is 1242: 1241: 1236:less than 10 is 1211: 1200: 1188: 1166: 1142: 878: 868: 858: 852: 837: 835: 834: 829: 827: 826: 817: 792: 789: 785: 780: 766: 757: 732: 729: 725: 717: 685: 681: 670: 663: 656: 652: 648: 640: 630: 626: 618: 602: 591: 589: 588: 583: 575: 574: 558: 556: 555: 550: 539:, there is some 538: 536: 535: 530: 512: 494: 490: 486: 483:is the value of 482: 473: 471: 470: 465: 463: 462: 447: 444: 437: 436: 399: 396: 378: 377: 356: 354: 353: 348: 346: 345: 336: 311: 308: 285: 260: 257: 250: 212: 189:positive integer 166: 162: 150: 146: 120:Jeffrey Lagarias 100: 98: 83:positive integer 35: 21: 18:Collatz sequence 9461: 9460: 9456: 9455: 9454: 9452: 9451: 9450: 9421: 9420: 9401: 9383: 9365: 9353:"Collatz Paths" 9350: 9341:Collatz Problem 9322: 9321: 9302:Wayback Machine 9284:Wayback Machine 9261: 9259: 9255: 9252: 9247: 9238: 9237: 9233: 9211: 9210: 9206: 9184: 9183: 9179: 9168: 9143: 9142: 9138: 9128: 9127: 9123: 9113: 9111: 9105: 9104: 9100: 9095: 9091: 9079: 9070: 9069: 9065: 9039: 9038: 9034: 9016: 9015: 9011: 8969: 8968: 8964: 8930: 8929: 8925: 8889: 8888: 8884: 8856: 8855: 8851: 8823: 8822: 8818: 8770: 8769: 8765: 8747: 8746: 8742: 8726: 8713: 8712: 8705: 8637: 8636: 8632: 8625:Quanta Magazine 8618: 8617: 8613: 8579: 8574: 8573: 8566: 8557: 8553: 8536: 8530: 8528: 8498: 8485: 8484: 8475: 8443: 8442: 8433: 8391: 8390: 8383: 8353: 8352: 8348: 8337: 8335: 8330: 8329: 8325: 8299: 8298: 8294: 8248: 8247: 8240: 8225: 8201: 8200: 8193: 8178: 8168:Springer-Verlag 8156:Guy, Richard K. 8154: 8153: 8149: 8142: 8120: 8119: 8115: 8108: 8087: 8086: 8082: 8072: 8071: 8067: 8058: 8054: 8018: 8017: 8000: 7990: 7977: 7976: 7972: 7968: 7963: 7962: 7932:Shizuo Kakutani 7920:Ulam conjecture 7905: 7890: 7887: 7883: 7878: 7848: 7838: 7831: 7828: 7808: 7774: 7769: 7768: 7764: 7757: 7753: 7748: 7745: 7744: 7743: 7741: 7725: 7721: 7710: 7706: 7692:halting problem 7683: 7672: 7668: 7664: 7656: 7650: 7646: 7640: 7636: 7630: 7622: 7619: 7616: 7615: 7613: 7611: 7605: 7598: 7587: 7584: 7574: 7564: 7557: 7551: 7494: 7478: 7457: 7456: 7442: 7436: 7420: 7413: 7409: 7405: 7394: 7391: 7384: 7383: 7381: 7372: 7368: 7355: 7340: 7336: 7329: 7310: 7291: 7281: 7264: 7259: 7247: 7243: 7239: 7228: 7223: 7219: 7214: 7205: 7197: 7193: 7190: 7178: 7174: 7170: 7166: 7162: 7154: 7153:, smaller than 7139: 7132: 7131:, smaller than 7118: 7114: 7110: 7106: 7069: 7062: 7058: 7054: 7050: 7037: 7030: 7022: 7016: 7006: 6991: 6987: 6983: 6979: 6964: 6960: 6956: 6952: 6948: 6944: 6909: 6902: 6898: 6894: 6890: 6886: 6882: 6873: 6868: 6806: 6805: 6768: 6767: 6731: 6724: 6720: 6659: 6658: 6617: 6616: 6574: 6573: 6531: 6530: 6527:critical points 6509: 6508: 6483: 6413: 6409: 6395: 6394: 6371: 6367: 6354: 6335: 6311: 6307: 6294: 6282: 6257: 6256: 6250:entire function 6221: 6220: 6184: 6167: 6166: 6095: 6091: 6074: 6073: 6043: 6042: 6007: 6006: 5974: 5973: 5954: 5953: 5930: 5929: 5877: 5873: 5860: 5838: 5833: 5832: 5800: 5796: 5783: 5761: 5756: 5755: 5721: 5699: 5673: 5640: 5639: 5616: 5615: 5605: 5596: 5595: 5585: 5572: 5549: 5544: 5543: 5525: 5524: 5514: 5505: 5504: 5494: 5481: 5458: 5453: 5452: 5428: 5423: 5422: 5401: 5396: 5395: 5372: 5371: 5329: 5328: 5300: 5299: 5280: 5279: 5252: 5251: 5233: 5179: 5175: 5167: 5166: 5140: 5135: 5134: 5122: 5096: 5063: 5062: 5058: 5017: 5016: 4993: 4988: 4987: 4983: 4965:2-adic integers 4941: 4936: 4935: 4918: 4917: 4885: 4866: 4861: 4860: 4828: 4811: 4790: 4789: 4786: 4765: 4764: 4729: 4710: 4705: 4704: 4669: 4652: 4629: 4624: 4623: 4612: 4608: 4601: 4597: 4587: 4584: 4581: 4580: 4578: 4574: 4570: 4524: 4511: 4510: 4499: 4489: 4476: 4466: 4453: 4443: 4430: 4420: 4419: 4412: 4411: 4408:(0 1 1 0 0 1 1) 4407: 4404:(1 0 1 1 0 0 1) 4403: 4281: 4280: 4243: 4230: 4229: 4218: 4208: 4195: 4185: 4172: 4162: 4149: 4139: 4138: 4131: 4130: 4127:(1 0 1 1 0 0 1) 4126: 4115: 4083: 4070: 4069: 4050: 4045: 4035: 4014: 4009: 3993: 3992: 3985: 3984: 3976: 3966: 3960: 3956: 3952: 3946:parity sequence 3939:2-adic integers 3934: 3925: 3909: 3903: 3897: 3891: 3886:β†’ βˆ’164 β†’ βˆ’82 β†’ 3885: 3879: 3873: 3867: 3849: 3843: 3837: 3819: 3813: 3795: 3789: 3762: 3758: 3754: 3749: 3734: 3727: 3723: 3719: 3705: 3695: 3685: 3643: 3642: 3626: 3607: 3602: 3601: 3585: 3568: 3547: 3546: 3541: 3539:As a tag system 3532: 3528: 3520: 3512: 3508: 3500: 3492: 3488: 3484: 3480: 3472: 3468: 3464: 3460: 3452: 3444: 3436: 3428: 3424: 3420: 3416: 3412: 3408: 3397: 3383: 3379: 3375: 3368: 3364: 3360: 3356: 3352: 3348: 3337: 3326: 3323: 3318: 3317: 3315: 3314: 3306: 3303: 3296: 3295: 3293: 3292: 3285: 3272: 3263: 3256: 3250: 3245: 3238: 3233: 3229: 3221: 3213: 3209: 3171: 3170: 3154: 3135: 3130: 3129: 3113: 3096: 3075: 3074: 3071: 3066: 3065: 3007: 3004: 2994: 2975: 2964: 2960: 2952: 2937: 2928: 2924: 2916: 2913: 2910: 2909: 2907: 2906: 2898: 2890: 2887: 2884: 2883: 2881: 2880: 2877: 2869: 2866: 2859: 2850: 2842: 2835: 2820: 2816: 2812: 2804: 2795: 2791: 2786:is the highest 2781: 2773: 2763: 2759: 2749: 2741: 2738: 2734: 2730: 2729: 2727: 2726: 2718: 2708: 2707:if and only if 2699: 2696: 2689: 2688: 2686: 2685: 2676: 2673: 2666: 2665: 2663: 2662: 2661:if and only if 2655: 2651: 2613: 2612: 2596: 2572: 2560: 2556: 2553: 2552: 2530: 2511: 2490: 2489: 2481: 2478: 2471: 2470: 2468: 2467: 2463: 2455: 2447:defined in the 2444: 2433: 2432:if and only if 2424: 2421: 2415: 2414: 2412: 2411: 2408:+ 1 ≑ 4 (mod 6) 2403: 2394: 2390: 2352: 2351: 2335: 2314: 2302: 2298: 2295: 2294: 2254: 2235: 2214: 2213: 2180: 2175: 2163: 2156: 2145: 2141: 2137: 2123: 2119: 2116: 2111: 2100: 2097: 2094: 2093: 2091: 2090: 2079: 2072: 2068: 2064: 2060: 2014: 2013: 2009: 2004: 2001: 1998: 1996: 1991: 1988: 1985: 1983: 1962: 1951: 1950: 1945: 1942: 1939: 1937: 1932: 1929: 1926: 1924: 1921: 1912: 1906: 1898: 1889: 1886: 1879: 1869: 1866: 1859: 1849: 1844: 1838: 1831: 1824: 1803: 1802: 1767: 1748: 1743: 1742: 1707: 1690: 1669: 1668: 1665: 1656: 1650: 1643: 1634:Quanta Magazine 1602: 1582: 1579: 1576: 1575: 1573: 1566: 1563: 1560: 1559: 1557: 1550: 1526:counterexamples 1516: 1514: 1511: 1503: 1496: 1493: 1484: 1481: 1472: 1468: 1465: 1456: 1449: 1443: 1441: 1437: 1433: 1429: 1425: 1422: 1413: 1410: 1401: 1392: 1388: 1376: 1373: 1370: 1368: 1363: 1360: 1357: 1355: 1341: 1336: 1333: 1330: 1328: 1320: 1317: 1314: 1312: 1304: 1301: 1298: 1296: 1288: 1285: 1283: 1275: 1272: 1270: 1262: 1259: 1257: 1249: 1247: 1239: 1237: 1207: 1201:to reach 1 are 1198: 1184: 1162: 1138: 1133: 1128:, 16, 8, 4, 2, 1127: 1121: 1115: 1109: 1104:, 184, 92, 46, 1103: 1097: 1091: 1085: 1079: 1073: 1067: 1061: 1055: 1049: 1043: 1037: 1031: 1025: 1019: 1013: 1007: 1001: 995: 989: 983: 977: 971: 965: 959: 953: 947: 941: 935: 929: 923: 917: 911: 905: 899: 893: 887: 873: 863: 854: 847: 844: 822: 821: 786: 767: 762: 761: 726: 709: 688: 687: 683: 675: 665: 661: 654: 650: 646: 637: 632: 628: 624: 617: 609: 604: 600: 566: 561: 560: 541: 540: 521: 520: 501: 496: 492: 488: 484: 480: 475: 458: 457: 441: 422: 413: 412: 393: 383: 369: 364: 363: 341: 340: 305: 290: 289: 254: 236: 215: 214: 210: 164: 160: 148: 144: 129: 96: 94: 56: 55: 50: 48: 37: 33: 28: 23: 22: 15: 12: 11: 5: 9459: 9457: 9449: 9448: 9443: 9438: 9433: 9423: 9422: 9419: 9418: 9413: 9399: 9381: 9363: 9348: 9338: 9319: 9312: 9305: 9287: 9270: 9251: 9250:External links 9248: 9246: 9245: 9231: 9220:(5): 351–367. 9204: 9177: 9166: 9136: 9121: 9098: 9089: 9063: 9052:(3): 241–252. 9032: 9009: 8962: 8943:(2): 145–151. 8923: 8882: 8849: 8816: 8763: 8740: 8703: 8658:(3): 237–258. 8630: 8611: 8590:(3): 241–252. 8564: 8551: 8473: 8431: 8381: 8346: 8323: 8292: 8238: 8223: 8205:, ed. (2010). 8191: 8176: 8147: 8140: 8113: 8106: 8080: 8065: 8052: 7998: 7988: 7969: 7967: 7964: 7961: 7960: 7940:Bryan Thwaites 7924:StanisΕ‚aw Ulam 7880: 7879: 7877: 7874: 7873: 7872: 7867: 7862: 7857: 7844: 7843: 7827: 7824: 7816:Turing machine 7807: 7804: 7781: 7777: 7763:Iterations of 7746: 7733: 7732: 7688: 7687: 7654: 7644: 7634: 7609: 7579: 7569: 7562: 7555: 7539: 7534: 7531: 7527: 7524: 7519: 7516: 7513: 7501: 7497: 7493: 7490: 7485: 7481: 7477: 7474: 7471: 7468: 7465: 7438:Main article: 7435: 7432: 7402: 7401: 7365: 7326: 7189: 7186: 7105:holds for all 7103: 7102: 7049: 7046: 7034:precomputation 7029:This requires 7027: 7026: 7020: 6943:The values of 6941: 6940: 6872: 6869: 6867: 6864: 6840: 6837: 6831: 6828: 6825: 6822: 6819: 6816: 6813: 6793: 6790: 6787: 6784: 6781: 6778: 6775: 6764: 6763: 6750: 6744: 6741: 6738: 6734: 6730: 6727: 6723: 6719: 6716: 6713: 6710: 6707: 6704: 6699: 6696: 6691: 6686: 6683: 6678: 6675: 6672: 6669: 6666: 6624: 6596: 6593: 6590: 6587: 6584: 6581: 6538: 6523: 6522: 6507: 6504: 6501: 6498: 6495: 6490: 6486: 6482: 6479: 6476: 6473: 6470: 6467: 6464: 6461: 6458: 6455: 6452: 6448: 6444: 6441: 6438: 6435: 6432: 6429: 6426: 6421: 6418: 6412: 6406: 6403: 6398: 6396: 6393: 6388: 6384: 6379: 6376: 6370: 6366: 6361: 6357: 6351: 6347: 6344: 6341: 6338: 6332: 6328: 6324: 6319: 6316: 6310: 6306: 6301: 6297: 6291: 6288: 6283: 6280: 6277: 6274: 6271: 6268: 6265: 6264: 6237: 6234: 6231: 6228: 6208: 6205: 6202: 6199: 6196: 6191: 6187: 6183: 6180: 6177: 6174: 6155: 6151: 6148: 6145: 6142: 6139: 6136: 6132: 6128: 6125: 6122: 6119: 6116: 6113: 6110: 6104: 6101: 6094: 6087: 6084: 6050: 6027: 6024: 6020: 6017: 6014: 5994: 5991: 5987: 5984: 5981: 5961: 5937: 5896: 5892: 5886: 5883: 5876: 5872: 5867: 5863: 5859: 5856: 5853: 5850: 5845: 5841: 5819: 5815: 5809: 5806: 5799: 5795: 5790: 5786: 5782: 5779: 5776: 5773: 5768: 5764: 5752: 5751: 5739: 5736: 5733: 5728: 5724: 5720: 5715: 5711: 5708: 5705: 5702: 5695: 5691: 5688: 5685: 5680: 5676: 5672: 5667: 5664: 5659: 5656: 5653: 5650: 5647: 5633: 5632: 5619: 5609: 5606: 5604: 5601: 5598: 5597: 5592: is even, 5589: 5586: 5584: 5581: 5578: 5577: 5575: 5570: 5567: 5564: 5561: 5556: 5552: 5541: 5528: 5518: 5515: 5513: 5510: 5507: 5506: 5501: is even, 5498: 5495: 5493: 5490: 5487: 5486: 5484: 5479: 5476: 5473: 5470: 5465: 5461: 5435: 5431: 5408: 5404: 5379: 5359: 5355: 5351: 5348: 5345: 5342: 5339: 5336: 5316: 5313: 5310: 5307: 5287: 5267: 5263: 5259: 5232: 5229: 5217: 5213: 5206: 5203: 5197: 5193: 5188: 5183: 5178: 5174: 5149: 5144: 5108: 5103: 5099: 5094: 5090: 5085: 5081: 5078: 5075: 5070: 5066: 5061: 5055: 5050: 5047: 5044: 5040: 5036: 5033: 5030: 5027: 5024: 5002: 4997: 4950: 4945: 4921: 4915: 4912: 4908: 4905: 4900: 4897: 4894: 4886: 4882: 4878: 4875: 4872: 4869: 4863: 4862: 4858: 4855: 4851: 4848: 4843: 4840: 4837: 4829: 4825: 4822: 4817: 4816: 4814: 4809: 4806: 4803: 4800: 4797: 4785: 4782: 4768: 4763: 4759: 4756: 4752: 4749: 4744: 4741: 4738: 4730: 4726: 4722: 4719: 4716: 4713: 4707: 4706: 4703: 4699: 4696: 4692: 4689: 4684: 4681: 4678: 4670: 4666: 4663: 4658: 4657: 4655: 4650: 4647: 4644: 4641: 4636: 4632: 4552: 4547: 4544: 4539: 4531: 4527: 4523: 4518: 4514: 4506: 4502: 4496: 4492: 4488: 4483: 4479: 4473: 4469: 4465: 4460: 4456: 4450: 4446: 4442: 4437: 4433: 4427: 4423: 4389: 4384: 4381: 4376: 4371: 4368: 4363: 4358: 4355: 4350: 4345: 4342: 4337: 4332: 4329: 4324: 4319: 4316: 4311: 4306: 4303: 4298: 4293: 4290: 4266: 4263: 4258: 4250: 4246: 4242: 4237: 4233: 4225: 4221: 4215: 4211: 4207: 4202: 4198: 4192: 4188: 4184: 4179: 4175: 4169: 4165: 4161: 4156: 4152: 4146: 4142: 4121: 4120: 4111: 4109: 4098: 4090: 4086: 4082: 4077: 4073: 4063: 4060: 4057: 4053: 4048: 4042: 4038: 4034: 4031: 4028: 4021: 4017: 4012: 4006: 4003: 4000: 3996: 3971: 3964: 3933: 3930: 3920: 3919: 3916: 3913: 3905: 3899: 3893: 3887: 3881: 3875: 3869: 3863: 3860: 3859: 3856: 3853: 3845: 3844:β†’ βˆ’20 β†’ βˆ’10 β†’ 3839: 3833: 3830: 3829: 3826: 3823: 3815: 3809: 3806: 3805: 3802: 3799: 3791: 3785: 3782: 3781: 3778: 3775: 3753: 3750: 3748: 3745: 3716: 3715: 3663: 3660: 3656: 3653: 3646: 3641: 3638: 3635: 3627: 3623: 3619: 3616: 3613: 3610: 3604: 3603: 3600: 3597: 3594: 3586: 3582: 3579: 3574: 3573: 3571: 3566: 3563: 3560: 3557: 3554: 3540: 3537: 3281: 3267: 3254: 3243: 3236: 3195: 3191: 3188: 3184: 3181: 3174: 3169: 3166: 3163: 3155: 3151: 3147: 3144: 3141: 3138: 3132: 3131: 3128: 3125: 3122: 3114: 3110: 3107: 3102: 3101: 3099: 3094: 3091: 3088: 3085: 3082: 3070: 3067: 3013: 3012: 3003: 3000: 2999: 2998: 2991: 2972: 2936: 2933: 2873: 2864: 2854: 2846: 2637: 2633: 2630: 2626: 2623: 2616: 2611: 2608: 2605: 2597: 2594: 2588: 2584: 2581: 2578: 2575: 2569: 2566: 2563: 2559: 2555: 2554: 2551: 2548: 2545: 2542: 2539: 2531: 2529: 2526: 2523: 2520: 2517: 2516: 2514: 2509: 2506: 2503: 2500: 2497: 2401:if and only if 2376: 2372: 2369: 2365: 2362: 2355: 2350: 2347: 2344: 2336: 2333: 2327: 2323: 2320: 2317: 2311: 2308: 2305: 2301: 2297: 2296: 2293: 2290: 2287: 2284: 2281: 2278: 2275: 2272: 2269: 2266: 2263: 2255: 2253: 2250: 2247: 2244: 2241: 2240: 2238: 2233: 2230: 2227: 2224: 2221: 2179: 2176: 2174: 2171: 2115: 2109: 2048: 2045: 2042: 2039: 2036: 2033: 2030: 2027: 2024: 2021: 1969: 1965: 1961: 1958: 1920: 1917: 1904: 1896: 1884: 1877: 1864: 1857: 1842: 1836: 1829: 1823:is a sequence 1806: 1801: 1797: 1794: 1790: 1787: 1782: 1779: 1776: 1768: 1764: 1760: 1757: 1754: 1751: 1745: 1744: 1741: 1737: 1734: 1730: 1727: 1722: 1719: 1716: 1708: 1704: 1701: 1696: 1695: 1693: 1688: 1685: 1682: 1679: 1676: 1664: 1661: 1642: 1639: 1610:parity vectors 1601: 1600:Stopping times 1598: 1549: 1546: 1510: 1507: 1502: 1499: 1498: 1497: 1494: 1487: 1485: 1482: 1475: 1473: 1466: 1459: 1457: 1423: 1416: 1414: 1411: 1404: 1400: 1399:Visualizations 1397: 1352: 1351: 1325: 1309: 1293: 1280: 1267: 1254: 1244: 1234: 1231: 1228: 1225: 1218: 1217: 1195: 1194: 1173: 1172: 1135: 1134: 1129: 1123: 1117: 1111: 1105: 1099: 1093: 1087: 1081: 1075: 1069: 1063: 1057: 1051: 1045: 1039: 1033: 1027: 1021: 1015: 1009: 1003: 997: 991: 985: 979: 973: 967: 961: 955: 949: 943: 937: 931: 925: 919: 913: 907: 901: 895: 889: 883: 843: 842:Empirical data 840: 825: 820: 816: 813: 809: 806: 801: 798: 795: 787: 783: 779: 776: 773: 770: 764: 763: 760: 756: 753: 749: 746: 741: 738: 735: 727: 723: 720: 715: 714: 712: 707: 704: 701: 698: 695: 641:is called the 635: 619:is called the 615: 607: 581: 578: 573: 569: 548: 528: 499: 478: 461: 456: 453: 450: 442: 440: 435: 432: 429: 425: 421: 418: 415: 414: 411: 408: 405: 402: 394: 392: 389: 388: 386: 381: 376: 372: 344: 339: 335: 332: 328: 325: 320: 317: 314: 306: 304: 301: 298: 295: 292: 291: 288: 284: 281: 277: 274: 269: 266: 263: 255: 253: 249: 245: 242: 241: 239: 234: 231: 228: 225: 222: 200: 199: 196: 128: 125: 106:Lothar Collatz 63:Directed graph 51: 47: 46: 43: 39: 38: 32: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 9458: 9447: 9444: 9442: 9439: 9437: 9434: 9432: 9429: 9428: 9426: 9417: 9414: 9410: 9409: 9404: 9400: 9396: 9392: 9391: 9386: 9382: 9378: 9374: 9373: 9368: 9364: 9360: 9359: 9354: 9349: 9346: 9342: 9339: 9334: 9333: 9328: 9325: 9320: 9317: 9313: 9310: 9306: 9303: 9299: 9296: 9292: 9288: 9285: 9281: 9278: 9275: 9271: 9267: 9254: 9253: 9249: 9241: 9235: 9232: 9227: 9223: 9219: 9215: 9208: 9205: 9200: 9196: 9192: 9188: 9187:Computability 9181: 9178: 9175: 9169: 9163: 9159: 9155: 9151: 9147: 9140: 9137: 9132: 9125: 9122: 9110:. p. 208 9109: 9102: 9099: 9093: 9090: 9085: 9078: 9076: 9067: 9064: 9059: 9055: 9051: 9047: 9043: 9036: 9033: 9029:(4): 495–509. 9028: 9024: 9020: 9013: 9010: 9005: 9001: 8996: 8991: 8987: 8983: 8982: 8977: 8975: 8966: 8963: 8958: 8954: 8950: 8946: 8942: 8938: 8934: 8927: 8924: 8919: 8915: 8910: 8905: 8901: 8897: 8893: 8886: 8883: 8877: 8872: 8868: 8864: 8860: 8853: 8850: 8844: 8839: 8835: 8831: 8827: 8820: 8817: 8812: 8808: 8803: 8798: 8794: 8790: 8786: 8782: 8778: 8776: 8767: 8764: 8759: 8755: 8751: 8744: 8741: 8736: 8732: 8725: 8723: 8720:-cycles with 8719: 8710: 8708: 8704: 8699: 8695: 8691: 8687: 8683: 8679: 8675: 8671: 8666: 8661: 8657: 8653: 8649: 8647: 8641: 8634: 8631: 8626: 8622: 8615: 8612: 8607: 8603: 8598: 8593: 8589: 8585: 8578: 8571: 8569: 8565: 8561: 8555: 8552: 8547: 8541: 8525: 8520: 8516: 8512: 8508: 8504: 8497: 8495: 8491: 8482: 8480: 8478: 8474: 8468: 8463: 8459: 8455: 8451: 8449: 8440: 8438: 8436: 8432: 8427: 8423: 8418: 8413: 8409: 8405: 8404: 8399: 8397: 8388: 8386: 8382: 8377: 8373: 8369: 8365: 8361: 8357: 8350: 8347: 8334: 8327: 8324: 8319: 8315: 8312:(11): 79–99. 8311: 8307: 8303: 8296: 8293: 8288: 8284: 8279: 8274: 8269: 8264: 8260: 8256: 8252: 8245: 8243: 8239: 8234: 8230: 8226: 8220: 8216: 8212: 8208: 8204: 8198: 8196: 8192: 8187: 8183: 8179: 8177:0-387-20860-7 8173: 8169: 8165: 8161: 8157: 8151: 8148: 8143: 8141:0-465-02685-0 8137: 8133: 8129: 8128: 8123: 8117: 8114: 8109: 8107:0-19-513342-0 8103: 8099: 8094: 8093: 8084: 8081: 8076: 8069: 8066: 8062: 8056: 8053: 8048: 8044: 8040: 8036: 8032: 8028: 8027: 8022: 8015: 8013: 8011: 8009: 8007: 8005: 8003: 7999: 7995: 7991: 7989:0-7890-0374-0 7985: 7981: 7974: 7971: 7965: 7957: 7953: 7949: 7945: 7941: 7937: 7933: 7929: 7925: 7921: 7917: 7913: 7909: 7902: 7898: 7894: 7885: 7882: 7875: 7871: 7868: 7866: 7863: 7861: 7858: 7856: 7852: 7846: 7845: 7841: 7835: 7830: 7825: 7823: 7821: 7817: 7813: 7805: 7803: 7801: 7797: 7779: 7775: 7761: 7739: 7728: 7717: 7713: 7704: 7703: 7702: 7700: 7695: 7694:in this way. 7693: 7679: 7675: 7662: 7661: 7660: 7653: 7643: 7633: 7608: 7601: 7594: 7590: 7582: 7578: 7572: 7568: 7561: 7554: 7537: 7529: 7525: 7517: 7514: 7511: 7499: 7495: 7491: 7488: 7483: 7479: 7475: 7469: 7463: 7453: 7451: 7447: 7441: 7433: 7431: 7427: 7423: 7416: 7388: 7379: 7375: 7366: 7363: 7358: 7351: 7347: 7343: 7332: 7327: 7322: 7318: 7315:+ 1) + 1 = 12 7314: 7306: 7302: 7298: 7294: 7288: 7284: 7279: 7278: 7277: 7274: 7272: 7267: 7258: 7254: 7250: 7242:from the set 7237: 7231: 7222: 7213: 7209: 7201: 7187: 7185: 7182: 7158: 7150: 7146: 7142: 7136: 7129: 7125: 7121: 7100: 7096: 7092: 7088: 7084: 7080: 7076: 7072: 7068: 7067: 7066: 7047: 7045: 7043: 7035: 7021: 7015: 7014: 7013: 7009: 7002: 6998: 6994: 6975: 6971: 6967: 6959:-bit numbers 6936: 6932: 6928: 6924: 6920: 6916: 6912: 6908: 6907: 6906: 6880: 6879: 6870: 6866:Optimizations 6865: 6863: 6861: 6857: 6838: 6835: 6829: 6826: 6823: 6817: 6811: 6791: 6788: 6782: 6776: 6773: 6748: 6742: 6739: 6736: 6732: 6728: 6725: 6721: 6714: 6711: 6708: 6705: 6697: 6694: 6689: 6684: 6681: 6676: 6670: 6664: 6657: 6656: 6655: 6653: 6644: 6640: 6638: 6622: 6614: 6610: 6594: 6591: 6585: 6579: 6567: 6562: 6558: 6556: 6552: 6536: 6528: 6502: 6499: 6493: 6488: 6484: 6477: 6471: 6468: 6462: 6459: 6453: 6450: 6446: 6439: 6436: 6430: 6427: 6424: 6419: 6416: 6410: 6404: 6401: 6391: 6386: 6382: 6377: 6374: 6368: 6364: 6359: 6355: 6349: 6345: 6342: 6339: 6336: 6330: 6326: 6322: 6317: 6314: 6308: 6304: 6299: 6295: 6289: 6286: 6278: 6272: 6266: 6255: 6254: 6253: 6251: 6232: 6226: 6203: 6200: 6194: 6189: 6185: 6178: 6172: 6153: 6146: 6143: 6137: 6134: 6130: 6123: 6120: 6114: 6111: 6108: 6102: 6099: 6092: 6085: 6082: 6071: 6067: 6066:complex plane 6062: 6048: 6041: 6022: 6018: 6015: 5989: 5985: 5982: 5959: 5951: 5935: 5927: 5926:monotonically 5923: 5920:, as well as 5919: 5915: 5911: 5894: 5890: 5884: 5881: 5874: 5870: 5865: 5861: 5857: 5851: 5843: 5839: 5817: 5813: 5807: 5804: 5797: 5793: 5788: 5784: 5780: 5774: 5766: 5762: 5734: 5726: 5722: 5718: 5713: 5709: 5706: 5703: 5700: 5693: 5686: 5678: 5674: 5670: 5665: 5662: 5657: 5651: 5645: 5638: 5637: 5636: 5612: is odd, 5607: 5602: 5599: 5587: 5582: 5579: 5573: 5568: 5562: 5554: 5550: 5542: 5521: is odd, 5516: 5511: 5508: 5496: 5491: 5488: 5482: 5477: 5471: 5463: 5459: 5451: 5450: 5449: 5433: 5429: 5406: 5402: 5393: 5392:interpolating 5377: 5357: 5353: 5346: 5343: 5340: 5337: 5314: 5311: 5308: 5305: 5285: 5265: 5261: 5257: 5249: 5241: 5237: 5230: 5228: 5215: 5204: 5201: 5195: 5191: 5186: 5176: 5172: 5163: 5147: 5132: 5128: 5121:The function 5119: 5106: 5101: 5097: 5092: 5088: 5083: 5076: 5068: 5064: 5059: 5048: 5045: 5042: 5038: 5034: 5028: 5022: 5000: 4981: 4980:parity vector 4976: 4974: 4970: 4966: 4948: 4910: 4906: 4898: 4895: 4892: 4880: 4876: 4873: 4870: 4867: 4853: 4849: 4841: 4838: 4835: 4823: 4820: 4812: 4807: 4801: 4795: 4788:The function 4783: 4781: 4761: 4754: 4750: 4742: 4739: 4736: 4724: 4720: 4717: 4714: 4711: 4701: 4694: 4690: 4682: 4679: 4676: 4664: 4661: 4653: 4648: 4642: 4634: 4630: 4620: 4616: 4605: 4594: 4568: 4563: 4550: 4545: 4542: 4537: 4529: 4525: 4521: 4516: 4512: 4504: 4500: 4494: 4490: 4486: 4481: 4477: 4471: 4467: 4463: 4458: 4454: 4448: 4444: 4440: 4435: 4431: 4425: 4421: 4400: 4387: 4382: 4379: 4369: 4366: 4356: 4353: 4343: 4340: 4330: 4327: 4317: 4314: 4304: 4301: 4291: 4288: 4264: 4261: 4256: 4248: 4244: 4240: 4235: 4231: 4223: 4219: 4213: 4209: 4205: 4200: 4196: 4190: 4186: 4182: 4177: 4173: 4167: 4163: 4159: 4154: 4150: 4144: 4140: 4119: 4112: 4110: 4096: 4088: 4084: 4080: 4075: 4071: 4061: 4058: 4055: 4051: 4046: 4040: 4036: 4032: 4029: 4026: 4019: 4015: 4010: 4004: 4001: 3998: 3994: 3983: 3982: 3979: 3974: 3970: 3963: 3949: 3947: 3942: 3940: 3931: 3929: 3917: 3914: 3912: 3908: 3902: 3896: 3890: 3884: 3878: 3872: 3866: 3862: 3861: 3857: 3854: 3852: 3848: 3842: 3836: 3832: 3831: 3827: 3824: 3822: 3818: 3812: 3808: 3807: 3803: 3800: 3798: 3794: 3788: 3784: 3783: 3779: 3776: 3773: 3772: 3769: 3766: 3751: 3746: 3744: 3742: 3741: 3731: 3712: 3708: 3702: 3698: 3692: 3688: 3684: 3683: 3682: 3680: 3675: 3658: 3654: 3639: 3636: 3633: 3621: 3617: 3614: 3611: 3608: 3598: 3595: 3592: 3580: 3577: 3569: 3564: 3558: 3552: 3544: 3538: 3536: 3524: 3516: 3504: 3496: 3476: 3456: 3448: 3440: 3432: 3405: 3401: 3394: 3390: 3386: 3374:Applying the 3372: 3344: 3340: 3334: 3321: 3300: 3289: 3284: 3280: 3276: 3270: 3266: 3260: 3253: 3246: 3239: 3225: 3217: 3206: 3193: 3186: 3182: 3167: 3164: 3161: 3149: 3145: 3142: 3139: 3136: 3126: 3123: 3120: 3108: 3105: 3097: 3092: 3086: 3080: 3068: 3064: 3060: 3059: 3054: 3050: 3049: 3044: 3040: 3039: 3034: 3030: 3029: 3024: 3020: 3019: 3011: 3001: 2992: 2987: 2983: 2979: 2973: 2968: 2958: 2957: 2956: 2950: 2946: 2943:that handles 2942: 2934: 2932: 2904: 2876: 2872: 2863: 2857: 2853: 2849: 2845: 2841: 2834:, the number 2833: 2827: 2823: 2810: 2802: 2794: 2790:that divides 2789: 2780: 2776: 2769: 2762: 2748: 2744: 2733: 2722: 2715: 2711: 2693: 2670: 2658: 2648: 2635: 2628: 2624: 2609: 2606: 2603: 2592: 2586: 2582: 2579: 2576: 2573: 2567: 2564: 2561: 2557: 2549: 2546: 2543: 2540: 2537: 2524: 2521: 2512: 2507: 2501: 2495: 2475: 2459: 2452: 2450: 2442: 2436: 2418: 2407: 2402: 2397: 2387: 2374: 2367: 2363: 2348: 2345: 2342: 2331: 2325: 2321: 2318: 2315: 2309: 2306: 2303: 2299: 2291: 2288: 2285: 2282: 2279: 2276: 2273: 2270: 2267: 2264: 2261: 2248: 2245: 2236: 2231: 2225: 2219: 2212: 2208: 2204: 2203:Collatz graph 2200: 2199:Collatz graph 2192: 2191: 2184: 2177: 2172: 2170: 2166: 2159: 2154: 2148: 2144:-cycle up to 2134: 2132: 2126: 2110: 2108: 2089:expansion of 2088: 2082: 2075: 2046: 2043: 2040: 2037: 2034: 2031: 2028: 2025: 2022: 2019: 1967: 1963: 1959: 1956: 1918: 1916: 1909: 1903: 1899: 1892: 1883: 1876: 1872: 1863: 1856: 1852: 1845: 1835: 1828: 1822: 1799: 1792: 1788: 1780: 1777: 1774: 1762: 1758: 1755: 1752: 1749: 1739: 1732: 1728: 1720: 1717: 1714: 1702: 1699: 1691: 1686: 1680: 1674: 1662: 1660: 1653: 1648: 1640: 1638: 1636: 1635: 1630: 1626: 1622: 1617: 1615: 1612:and uses the 1611: 1607: 1604:As proven by 1599: 1597: 1595: 1591: 1555: 1547: 1545: 1542: 1537: 1535: 1531: 1527: 1522: 1508: 1506: 1500: 1491: 1486: 1479: 1474: 1463: 1458: 1452: 1420: 1415: 1408: 1403: 1398: 1396: 1386: 1385:powers of two 1381: 1349: 1344: 1326: 1310: 1294: 1281: 1268: 1255: 1245: 1235: 1232: 1229: 1226: 1223: 1222: 1221: 1215: 1210: 1204: 1203: 1202: 1192: 1187: 1182: 1181: 1180: 1178: 1170: 1165: 1160: 1159: 1158: 1152: 1148: 1146: 1141: 1132: 1126: 1120: 1114: 1108: 1102: 1096: 1092:, 1300, 650, 1090: 1086:, 1732, 866, 1084: 1078: 1072: 1066: 1060: 1054: 1048: 1042: 1036: 1030: 1024: 1020:, 1276, 638, 1018: 1012: 1008:, 1132, 566, 1006: 1000: 994: 988: 984:, 1780, 890, 982: 976: 970: 964: 958: 952: 946: 940: 934: 928: 922: 916: 910: 904: 898: 892: 886: 882: 881: 880: 876: 870: 866: 860: 857: 850: 841: 839: 818: 811: 807: 799: 796: 793: 781: 777: 774: 771: 768: 758: 751: 747: 739: 736: 733: 721: 718: 710: 705: 699: 693: 679: 672: 668: 658: 644: 638: 622: 621:stopping time 614: 610: 599:The smallest 597: 593: 579: 576: 571: 567: 546: 526: 519: 514: 510: 506: 502: 481: 454: 451: 448: 433: 430: 427: 423: 416: 409: 406: 403: 400: 390: 384: 379: 374: 370: 362:In notation: 360: 357: 337: 330: 326: 318: 315: 312: 302: 299: 296: 293: 286: 279: 275: 267: 264: 261: 251: 247: 243: 237: 232: 226: 220: 209: 205: 197: 194: 193: 192: 190: 181: 173: 157: 141: 133: 126: 124: 121: 117: 113: 111: 107: 102: 92: 88: 84: 80: 76: 68: 64: 60: 54: 44: 41: 40: 30: 19: 9407: 9389: 9385:Eisenbud, D. 9371: 9367:Eisenbud, D. 9356: 9330: 9234: 9217: 9213: 9207: 9193:(1): 19–56. 9190: 9186: 9180: 9149: 9139: 9130: 9124: 9112:. Retrieved 9101: 9092: 9083: 9074: 9066: 9049: 9045: 9041: 9035: 9026: 9022: 9018: 9012: 8985: 8979: 8973: 8965: 8940: 8936: 8926: 8902:(1): 33–53. 8899: 8895: 8885: 8866: 8862: 8852: 8833: 8829: 8819: 8784: 8780: 8777:+ 1 problem" 8774: 8766: 8749: 8743: 8734: 8730: 8721: 8717: 8665:math/0205002 8655: 8651: 8645: 8633: 8624: 8614: 8587: 8583: 8554: 8540:cite journal 8529:. Retrieved 8509:(1): 51–70. 8506: 8502: 8493: 8489: 8460:(1): 45–56. 8457: 8453: 8447: 8410:(1): 19–22. 8407: 8401: 8395: 8359: 8355: 8349: 8336:. Retrieved 8326: 8309: 8305: 8301: 8295: 8258: 8254: 8210: 8206: 8163: 8150: 8126: 8116: 8091: 8083: 8068: 8055: 8030: 8024: 8020: 7993: 7979: 7973: 7951: 7948:Helmut Hasse 7943: 7935: 7927: 7919: 7915: 7907: 7904: 7900: 7892: 7889: 7884: 7850: 7809: 7762: 7734: 7726: 7715: 7711: 7698: 7696: 7689: 7677: 7673: 7651: 7641: 7631: 7606: 7599: 7592: 7588: 7580: 7576: 7570: 7566: 7559: 7552: 7454: 7443: 7425: 7421: 7414: 7403: 7386: 7377: 7373: 7367:For all odd 7356: 7349: 7348:βˆ’ 1) = 2 Γ— 3 7345: 7341: 7330: 7320: 7316: 7312: 7304: 7300: 7296: 7292: 7286: 7282: 7275: 7256: 7252: 7248: 7235: 7229: 7220: 7211: 7207: 7204:is even, so 7199: 7191: 7183: 7156: 7148: 7144: 7140: 7134: 7127: 7123: 7119: 7104: 7098: 7094: 7090: 7086: 7082: 7078: 7074: 7070: 7051: 7028: 7007: 7000: 6996: 6992: 6973: 6969: 6965: 6942: 6934: 6930: 6926: 6922: 6918: 6914: 6910: 6905:is given by 6876: 6875:The section 6874: 6859: 6855: 6765: 6649: 6571: 6551:Baker domain 6524: 6063: 5918:fixed points 5753: 5634: 5245: 5164: 5125:is a 2-adic 5120: 4979: 4977: 4787: 4618: 4614: 4606: 4595: 4566: 4564: 4401: 4124: 4113: 3972: 3968: 3967:< β‹― < 3961: 3950: 3943: 3935: 3923: 3910: 3906: 3900: 3894: 3888: 3882: 3876: 3870: 3864: 3850: 3846: 3840: 3834: 3820: 3816: 3810: 3796: 3792: 3786: 3767: 3755: 3738: 3732: 3717: 3710: 3706: 3700: 3696: 3690: 3686: 3679:2-tag system 3676: 3545: 3542: 3522: 3514: 3502: 3494: 3474: 3454: 3446: 3438: 3430: 3403: 3399: 3392: 3388: 3384: 3373: 3342: 3338: 3335: 3319: 3298: 3290: 3282: 3278: 3274: 3268: 3264: 3258: 3251: 3241: 3234: 3223: 3215: 3207: 3072: 3062: 3057: 3055: 3052: 3047: 3045: 3042: 3037: 3035: 3032: 3027: 3025: 3022: 3017: 3015: 3014:111 3005: 2985: 2981: 2977: 2966: 2938: 2874: 2870: 2861: 2855: 2851: 2847: 2843: 2830:). Then in 2825: 2821: 2792: 2778: 2774: 2767: 2760: 2746: 2742: 2731: 2720: 2716: 2709: 2691: 2668: 2656: 2649: 2473: 2457: 2453: 2434: 2416: 2405: 2395: 2388: 2202: 2198: 2196: 2187: 2164: 2157: 2155:-cycle with 2152: 2146: 2135: 2130: 2124: 2117: 2080: 2073: 1922: 1919:Cycle length 1910: 1901: 1894: 1890: 1881: 1874: 1870: 1861: 1854: 1850: 1840: 1833: 1826: 1666: 1651: 1644: 1641:Lower bounds 1632: 1618: 1603: 1553: 1551: 1541:lower bounds 1538: 1523: 1512: 1504: 1450: 1382: 1353: 1219: 1196: 1174: 1156: 1136: 1130: 1124: 1118: 1112: 1106: 1100: 1094: 1088: 1082: 1076: 1070: 1064: 1058: 1052: 1046: 1040: 1034: 1028: 1022: 1016: 1010: 1004: 998: 992: 986: 980: 974: 968: 962: 960:, 700, 350, 956: 950: 944: 942:, 412, 206, 938: 932: 930:, 364, 182, 926: 924:, 484, 242, 920: 914: 908: 902: 896: 890: 884: 874: 871: 864: 861: 855: 848: 845: 677: 673: 666: 659: 642: 633: 620: 612: 605: 598: 594: 517: 515: 508: 504: 497: 491:recursively 476: 361: 358: 213:as follows: 201: 186: 114: 103: 74: 72: 65:showing the 29: 9431:Conjectures 9272:An ongoing 8869:: 135–141. 8787:: 1565–72. 8211:+ 1 Problem 8033:(1): 3–23. 7812:Busy Beaver 7450:undecidable 7309:. (Because 6947:(or better 5240:Cobweb plot 4978:Define the 4567:irreducible 2868:where each 2809:odd numbers 2712:≑ 2 (mod 3) 2705:≑ 1 (mod 2) 2682:≑ 2 (mod 3) 2659:≑ 1 (mod 2) 2437:≑ 4 (mod 6) 2430:≑ 1 (mod 2) 2398:≑ 1 (mod 2) 1888:, ..., and 1621:Terence Tao 1606:Riho Terras 1436:axis: some 894:, 124, 62, 862:The number 487:applied to 9425:Categories 9345:PlanetMath 8781:Math. Comp 8722:m <= 91 8531:2023-03-28 8268:1909.03562 8233:1253.11003 8186:1058.11001 7966:References 7950:), or the 7916:conjecture 7901:conjecture 7820:Paul ErdΕ‘s 7724:, for all 7419:such that 7263:(sequence 6564:A Collatz 5950:attracting 5910:iterations 5131:almost all 4986:acting on 3790:β†’ 4 β†’ 2 β†’ 3740:Tag system 3726:copies of 2807:maps from 2788:power of 2 2178:In reverse 1629:almost all 1594:almost all 1391:is halved 1137:(sequence 631:such that 603:such that 474:(that is: 116:Paul ErdΕ‘s 110:hailstones 9332:MathWorld 9004:0008-414X 8918:0065-1036 8376:220294340 8287:2050-5086 7855:semigroup 7760:to 6480. 7701:problem: 7515:≡ 7444:In 1972, 7319:+ 4 = 4(3 6986:times to 6982:function 6824:≈ 6789:≫ 6777:⁡ 6740:π 6729:− 6677:≜ 6613:Julia set 6592:≜ 6500:π 6494:⁡ 6460:π 6454:⁡ 6437:π 6431:⁡ 6425:− 6405:π 6375:π 6365:⁡ 6315:π 6305:⁡ 6279:≜ 6201:π 6195:⁡ 6144:π 6138:⁡ 6121:π 6115:⁡ 6109:− 6086:π 6023:2.1386... 6016:1.1925... 5924:escaping 5882:π 5871:⁡ 5858:≜ 5805:π 5794:⁡ 5781:≜ 5719:⋅ 5671:⋅ 5658:≜ 5448:, where: 5248:real line 5196:⊂ 5054:∞ 5039:∑ 4982:function 4896:≡ 4839:≡ 4740:≡ 4680:≡ 4575:(1 1 0 0) 4522:− 4375:→ 4362:→ 4349:→ 4336:→ 4323:→ 4310:→ 4297:→ 4241:− 4081:− 4059:− 4030:⋯ 4002:− 3898:β†’ βˆ’182 β†’ 3892:β†’ βˆ’122 β†’ 3880:β†’ βˆ’110 β†’ 3637:≡ 3596:≡ 3419:times to 3415:function 3378:function 3165:≡ 3124:≡ 2955:remains: 2903:repetends 2801:remainder 2799:(with no 2607:≡ 2580:− 2541:≡ 2346:≡ 2319:− 2265:≡ 1960:× 1778:≡ 1718:≡ 1619:In 2019, 797:≡ 737:≡ 445:for  431:− 397:for  316:≡ 265:≡ 9395:Archived 9377:Archived 9298:Archived 9280:Archived 8957:17925995 8698:18467460 8642:(2003). 8338:14 March 8158:(2004). 8124:(1979). 7826:See also 7800:FRACTRAN 7440:FRACTRAN 7354:. (Here 7335:and odd 7280:For all 7227:odd and 7147:+ 1) = 3 7093:) < 2 7053:of  6963:, where 6219:, where 5948:has two 5127:isometry 4889:if  4832:if  4733:if  4673:if  3874:β†’ βˆ’74 β†’ 3868:β†’ βˆ’50 β†’ 3838:β†’ βˆ’14 β†’ 3630:if  3589:if  3519:becomes 3499:becomes 3407:, where 3249:, where 3226:+ 1) = 1 3158:if  3117:if  2600:if  2534:if  2339:if  2258:if  2211:relation 2188:Collatz 2044:85137581 2035:17087915 1771:if  1711:if  1074:, 6154, 1068:, 4102, 1062:, 2734, 1050:, 4858, 1044:, 3238, 1038:, 2158, 1032:, 1438, 978:, 1186, 790:if  730:if  507: ( 495:times; 309:if  258:if  208:function 9316:project 9309:project 9295:project 9277:project 9114:26 July 8811:2137019 8789:Bibcode 8758:0535032 8690:1980260 8670:Bibcode 8606:0568274 8511:Bibcode 8426:2044308 8261:: e12. 8047:2322189 7954:(after 7946:(after 7938:(after 7934:), the 7930:(after 7922:(after 7918:), the 7912:problem 7903:), the 7897:problem 7798:called 7626:⁠ 7614:⁠ 7565:, ..., 7398:⁠ 7382:⁠ 7380:βˆ’ 1) ≀ 7299:+ 1) = 7269:in the 7266:A075677 7234:. The 7210:+ 1 = 2 7113:modulo 6804:, then 6637:fractal 6566:fractal 6248:is any 6040:measure 4973:ergodic 4591:⁠ 4579:⁠ 3814:β†’ βˆ’2 β†’ 3477:+ 3 βˆ’ 1 3459:. When 3330:⁠ 3316:⁠ 3310:⁠ 3294:⁠ 3002:Example 2959:Append 2945:strings 2920:⁠ 2908:⁠ 2894:⁠ 2882:⁠ 2840:strings 2755:⁠ 2728:⁠ 2703:⁠ 2687:⁠ 2680:⁠ 2664:⁠ 2485:⁠ 2469:⁠ 2428:⁠ 2413:⁠ 2131:1-cycle 2114:-cycles 2104:⁠ 2092:⁠ 1839:, ..., 1627:, that 1625:density 1586:⁠ 1574:⁠ 1570:⁠ 1558:⁠ 1346:in the 1343:A284668 1212:in the 1209:A006577 1189:in the 1186:A006884 1177:maximum 1167:in the 1164:A006877 1143:in the 1140:A008884 1116:, 106, 1026:, 958, 1014:, 850, 1002:, 754, 996:, 502, 972:, 790, 966:, 526, 954:, 466, 948:, 310, 936:, 274, 918:, 322, 912:, 214, 906:, 142, 9164:  9002:  8972:"The 3 8955:  8916:  8809:  8756:  8696:  8688:  8604:  8446:"The 3 8424:  8374:  8285:  8231:  8221:  8184:  8174:  8138:  8104:  8100:–118. 8045:  7986:  7729:> 0 7720:reach 7705:Given 7682:reach 7663:Given 7550:where 6990:, and 6951:) and 5922:orbits 5908:. The 3443:; for 3423:, and 3262:, and 3210:P(...) 2980:+ 1 + 2832:binary 2758:where 2201:. The 2138:(1; 2) 2059:where 2026:301994 1663:Cycles 1590:2-adic 1453:= 9663 1387:since 1110:, 70, 900:, 94, 888:, 82, 674:Since 67:orbits 9291:BOINC 9266:page" 9080:(PDF) 8953:S2CID 8727:(PDF) 8694:S2CID 8660:arXiv 8580:(PDF) 8499:(PDF) 8422:JSTOR 8372:S2CID 8263:arXiv 8132:400–2 8043:JSTOR 7876:Notes 7428:) = 1 7218:with 7081:) = 3 6921:) = 3 6893:(the 6858:, or 6856:hairs 5278:when 4602:(0 1) 4598:(1 0) 3774:Cycle 3465:2 βˆ’ 1 3218:) = 0 3036:10001 3031:10001 2828:) = 1 2725:with 2207:graph 2205:is a 2190:graph 1913:(1,2) 1821:cycle 1645:In a 1448:(for 611:< 559:with 167:axis. 151:axis. 9162:ISBN 9116:2024 9000:ISSN 8914:ISSN 8546:link 8340:2020 8283:ISSN 8219:ISBN 8172:ISBN 8136:ISBN 8102:ISBN 7984:ISBN 7914:(or 7899:(or 7736:the 7667:and 7323:+ 1) 7271:OEIS 7255:) = 7126:) = 7061:and 7040:, a 6860:rays 6005:and 5831:and 5421:and 4600:and 3511:and 3363:and 3351:and 3240:= P( 3220:and 3063:0000 3046:1101 3041:1101 3026:1011 3021:1011 2949:bits 2860:... 2772:and 2441:tree 2160:≀ 91 2149:= 68 2101:ln 2 2095:ln 3 2078:and 2067:and 1936:(or 1900:) = 1880:) = 1860:) = 1532:and 1515:2.95 1424:The 1348:OEIS 1214:OEIS 1191:OEIS 1169:OEIS 1145:OEIS 1077:3077 1071:2051 1065:1367 1053:2429 1047:1619 1041:1079 877:= 27 867:= 19 851:= 12 452:> 95:2.95 91:even 73:The 9343:at 9264:+ 1 9222:doi 9195:doi 9174:PDF 9172:As 9154:doi 9054:doi 8990:doi 8945:doi 8904:doi 8871:doi 8867:618 8838:doi 8834:412 8797:doi 8678:doi 8656:109 8592:doi 8519:doi 8507:117 8462:doi 8458:118 8412:doi 8364:doi 8314:doi 8273:doi 8229:Zbl 8182:Zbl 8098:116 8035:doi 7942:), 7926:), 7910:+ 1 7895:+ 1 7853:+ 1 7657:= 1 7647:= 3 7637:= 0 7602:= 2 7583:βˆ’ 1 7573:βˆ’ 1 7526:mod 7417:β‰₯ 1 7408:in 7389:βˆ’ 1 7360:is 7352:βˆ’ 1 7333:β‰₯ 1 7311:3(4 7273:). 7232:β‰₯ 1 7202:+ 1 7192:If 7159:+ 1 7151:+ 1 7010:= 5 6615:of 6529:of 6485:sin 6451:sin 6428:cos 6356:sin 6296:cos 6186:sin 6135:sin 6112:cos 5862:sin 5785:cos 5327:or 5084:mod 5015:as 4963:of 4907:mod 4850:mod 4751:mod 4691:mod 4543:250 4380:151 4354:170 4341:340 4328:211 4315:125 4302:250 4289:151 4262:151 3918:18 3911:... 3907:βˆ’17 3901:βˆ’91 3895:βˆ’61 3889:βˆ’41 3883:βˆ’55 3877:βˆ’37 3871:βˆ’25 3865:βˆ’17 3851:... 3821:... 3797:... 3711:aaa 3655:mod 3525:+ 2 3517:+ 3 3505:+ 1 3497:+ 1 3463:is 3457:+ 1 3449:+ 1 3441:+ 2 3433:+ 1 3387:= 2 3313:or 3301:+ 1 3232:as 3222:P(2 3214:P(2 3208:If 3183:mod 3056:101 3053:000 3051:101 3016:111 3008:111 2988:+ 1 2984:= 3 2969:+ 1 2947:of 2931:). 2905:of 2770:+ 1 2766:= 3 2723:+ 1 2694:βˆ’ 1 2671:+ 1 2625:mod 2476:+ 1 2460:+ 1 2419:βˆ’ 1 2364:mod 2083:= 0 2076:β‰₯ 1 2005:929 2002:839 1999:504 1997:355 1992:617 1989:794 1986:976 1984:217 1946:595 1943:759 1940:265 1938:186 1933:604 1930:327 1927:208 1925:114 1789:mod 1729:mod 1554:odd 1442:2.7 1377:630 1374:657 1371:780 1364:631 1361:657 1358:780 1337:647 1334:275 1331:345 1329:989 1321:247 1318:138 1315:128 1305:630 1302:657 1299:780 1289:279 1286:617 1284:670 1276:127 1273:728 1263:511 1260:400 1250:799 1248:837 1240:031 1095:325 1089:433 1083:577 1059:911 1035:719 1029:479 1023:319 1017:425 1011:283 1005:377 999:251 993:167 987:445 981:593 975:395 969:263 963:175 957:233 951:155 945:103 939:137 927:121 921:161 915:107 808:mod 748:mod 680:+ 1 669:β‰₯ 2 653:or 645:of 639:= 1 623:of 513:). 327:mod 276:mod 202:In 9427:: 9355:. 9347:.. 9329:. 9260:3 9218:32 9216:. 9189:. 9160:. 9082:. 9048:. 9025:. 8998:. 8986:48 8984:. 8978:. 8951:. 8939:. 8935:. 8912:. 8900:56 8898:. 8894:. 8865:. 8861:. 8832:. 8828:. 8807:MR 8805:. 8795:. 8785:74 8783:. 8779:. 8754:MR 8735:26 8733:. 8729:. 8706:^ 8692:. 8686:MR 8684:. 8676:. 8668:. 8654:. 8650:. 8623:. 8602:MR 8600:. 8588:30 8586:. 8582:. 8567:^ 8542:}} 8538:{{ 8517:. 8505:. 8501:. 8476:^ 8456:. 8452:. 8434:^ 8420:. 8408:82 8406:. 8400:. 8384:^ 8370:. 8360:77 8358:. 8310:24 8308:. 8281:. 8271:. 8259:10 8257:. 8253:. 8241:^ 8227:. 8217:. 8213:. 8194:^ 8180:. 8162:. 8134:. 8041:. 8031:92 8029:. 8001:^ 7992:. 7958:). 7802:. 7649:, 7639:, 7629:, 7612:= 7604:, 7575:, 7558:, 7452:. 7430:. 7376:(2 7371:, 7364:.) 7344:(2 7339:, 7325:.) 7295:(4 7290:, 7285:∈ 7143:(4 7122:(2 7097:+ 7085:+ 7077:+ 7073:(2 7044:. 6999:, 6972:, 6933:, 6925:+ 6917:+ 6913:(2 6862:. 6774:Im 6061:. 5972:: 5162:. 4975:. 4617:+ 4546:47 4383:47 4370:47 4367:85 4357:47 4344:47 4331:47 4318:47 4305:47 4292:47 4265:47 3975:βˆ’1 3858:5 3847:βˆ’5 3841:βˆ’7 3835:βˆ’5 3828:2 3817:βˆ’1 3811:βˆ’1 3804:3 3765:: 3709:β†’ 3704:, 3699:β†’ 3694:, 3691:bc 3689:β†’ 3640:1. 3535:. 3513:16 3402:+ 3391:+ 3288:. 3273:= 3271:+1 3257:= 3043:00 2990:); 2971:); 2858:βˆ’1 2654:, 2393:, 2133:. 2118:A 2107:. 2081:ac 2063:, 1968:69 1908:. 1868:, 1832:, 1819:A 1659:. 1616:. 1536:. 1519:10 1446:10 1380:. 1313:75 1271:63 1238:77 1171:). 1147:) 1119:53 1113:35 1107:23 1101:61 933:91 909:71 903:47 897:31 891:41 885:27 592:. 503:= 191:: 99:10 9361:. 9335:. 9289:( 9268:. 9262:x 9258:" 9242:. 9228:. 9224:: 9201:. 9197:: 9191:1 9170:. 9156:: 9118:. 9086:. 9075:x 9060:. 9056:: 9050:8 9042:n 9027:2 9019:x 9006:. 8992:: 8974:x 8959:. 8947:: 8941:7 8920:. 8906:: 8879:. 8873:: 8846:. 8840:: 8813:. 8799:: 8791:: 8775:x 8760:. 8724:" 8718:m 8700:. 8680:: 8672:: 8662:: 8646:x 8627:. 8608:. 8594:: 8562:. 8548:) 8534:. 8521:: 8513:: 8494:n 8490:m 8470:. 8464:: 8448:x 8428:. 8414:: 8396:n 8378:. 8366:: 8342:. 8320:. 8316:: 8302:x 8289:. 8275:: 8265:: 8235:. 8209:x 8188:. 8144:. 8110:. 8063:. 8049:. 8037:: 8021:x 7908:x 7906:3 7893:n 7891:3 7851:x 7849:3 7780:i 7776:b 7765:g 7758:P 7754:g 7747:2 7742:Ξ  7731:? 7727:n 7722:1 7718:) 7716:n 7714:( 7712:g 7707:g 7686:? 7684:1 7680:) 7678:n 7676:( 7674:g 7669:n 7665:g 7655:1 7652:b 7645:1 7642:a 7635:0 7632:b 7623:2 7620:/ 7617:1 7610:0 7607:a 7600:P 7595:) 7593:n 7591:( 7589:g 7581:P 7577:b 7571:P 7567:a 7563:0 7560:b 7556:0 7553:a 7538:, 7533:) 7530:P 7523:( 7518:i 7512:n 7500:i 7496:b 7492:+ 7489:n 7484:i 7480:a 7476:= 7473:) 7470:n 7467:( 7464:g 7426:k 7424:( 7422:f 7415:n 7410:I 7406:k 7395:2 7392:/ 7387:h 7385:3 7378:h 7374:f 7369:h 7357:f 7350:h 7346:h 7342:f 7337:h 7331:p 7321:k 7317:k 7313:k 7307:) 7305:k 7303:( 7301:f 7297:k 7293:f 7287:I 7283:k 7260:β€² 7257:k 7253:k 7251:( 7249:f 7244:I 7240:f 7230:a 7224:β€² 7221:k 7215:β€² 7212:k 7208:k 7206:3 7200:k 7198:3 7194:k 7179:k 7175:b 7171:k 7167:k 7163:a 7157:n 7155:4 7149:n 7145:n 7141:f 7135:n 7133:2 7128:n 7124:n 7120:f 7115:2 7111:b 7107:a 7099:b 7095:a 7091:b 7089:( 7087:d 7083:a 7079:b 7075:a 7071:f 7063:k 7059:b 7055:n 7038:k 7031:2 7023:d 7017:c 7008:k 7003:) 7001:k 6997:b 6995:( 6993:c 6988:b 6984:k 6980:f 6976:) 6974:k 6970:b 6968:( 6966:d 6961:b 6957:k 6953:d 6949:3 6945:c 6939:. 6937:) 6935:k 6931:b 6929:( 6927:d 6923:a 6919:b 6915:a 6911:f 6903:k 6899:a 6895:k 6891:b 6887:f 6883:k 6839:4 6836:1 6830:+ 6827:z 6821:) 6818:z 6815:( 6812:f 6792:1 6786:) 6783:z 6780:( 6762:, 6749:) 6743:z 6737:i 6733:e 6726:1 6722:( 6718:) 6715:1 6712:+ 6709:z 6706:2 6703:( 6698:4 6695:1 6690:+ 6685:2 6682:z 6674:) 6671:z 6668:( 6665:f 6623:f 6595:0 6589:) 6586:z 6583:( 6580:h 6537:f 6506:) 6503:z 6497:( 6489:2 6481:) 6478:z 6475:( 6472:h 6469:+ 6466:) 6463:z 6457:( 6447:) 6443:) 6440:z 6434:( 6420:2 6417:1 6411:( 6402:1 6392:+ 6387:) 6383:z 6378:2 6369:( 6360:2 6350:2 6346:1 6343:+ 6340:z 6337:3 6331:+ 6327:) 6323:z 6318:2 6309:( 6300:2 6290:2 6287:z 6276:) 6273:z 6270:( 6267:f 6236:) 6233:z 6230:( 6227:h 6207:) 6204:z 6198:( 6190:2 6182:) 6179:z 6176:( 6173:h 6154:+ 6150:) 6147:z 6141:( 6131:) 6127:) 6124:z 6118:( 6103:2 6100:1 6093:( 6083:1 6049:0 6026:) 6019:; 6013:( 5993:) 5990:2 5986:; 5983:1 5980:( 5960:2 5936:f 5895:) 5891:x 5885:2 5875:( 5866:2 5855:) 5852:x 5849:( 5844:2 5840:g 5818:) 5814:x 5808:2 5798:( 5789:2 5778:) 5775:x 5772:( 5767:1 5763:g 5750:. 5738:) 5735:x 5732:( 5727:2 5723:g 5714:2 5710:1 5707:+ 5704:x 5701:3 5694:+ 5690:) 5687:x 5684:( 5679:1 5675:g 5666:2 5663:x 5655:) 5652:x 5649:( 5646:f 5608:n 5603:, 5600:1 5588:n 5583:, 5580:0 5574:{ 5569:= 5566:) 5563:n 5560:( 5555:2 5551:g 5517:n 5512:, 5509:0 5497:n 5492:, 5489:1 5483:{ 5478:= 5475:) 5472:n 5469:( 5464:1 5460:g 5434:2 5430:g 5407:1 5403:g 5378:x 5358:2 5354:/ 5350:) 5347:1 5344:+ 5341:x 5338:3 5335:( 5315:1 5312:+ 5309:x 5306:3 5286:x 5266:2 5262:/ 5258:x 5216:. 5212:Z 5205:3 5202:1 5192:) 5187:+ 5182:Z 5177:( 5173:Q 5148:2 5143:Z 5123:Q 5107:. 5102:k 5098:2 5093:) 5089:2 5080:) 5077:x 5074:( 5069:k 5065:T 5060:( 5049:0 5046:= 5043:k 5035:= 5032:) 5029:x 5026:( 5023:Q 5001:2 4996:Z 4984:Q 4949:2 4944:Z 4914:) 4911:2 4904:( 4899:1 4893:x 4881:2 4877:1 4874:+ 4871:x 4868:3 4857:) 4854:2 4847:( 4842:0 4836:x 4824:2 4821:x 4813:{ 4808:= 4805:) 4802:x 4799:( 4796:T 4762:. 4758:) 4755:2 4748:( 4743:1 4737:x 4725:2 4721:d 4718:+ 4715:x 4712:3 4702:, 4698:) 4695:2 4688:( 4683:0 4677:x 4665:2 4662:x 4654:{ 4649:= 4646:) 4643:x 4640:( 4635:d 4631:T 4619:d 4615:n 4613:3 4609:d 4588:7 4585:/ 4582:5 4551:. 4538:= 4530:4 4526:3 4517:7 4513:2 4505:6 4501:2 4495:0 4491:3 4487:+ 4482:5 4478:2 4472:1 4468:3 4464:+ 4459:2 4455:2 4449:2 4445:3 4441:+ 4436:1 4432:2 4426:3 4422:3 4388:. 4257:= 4249:4 4245:3 4236:7 4232:2 4224:6 4220:2 4214:0 4210:3 4206:+ 4201:3 4197:2 4191:1 4187:3 4183:+ 4178:2 4174:2 4168:2 4164:3 4160:+ 4155:0 4151:2 4145:3 4141:3 4118:) 4116:1 4114:( 4097:. 4089:m 4085:3 4076:n 4072:2 4062:1 4056:m 4052:k 4047:2 4041:0 4037:3 4033:+ 4027:+ 4020:0 4016:k 4011:2 4005:1 3999:m 3995:3 3973:m 3969:k 3965:0 3962:k 3957:m 3953:n 3926:f 3915:7 3855:2 3825:1 3801:1 3793:1 3787:1 3763:n 3759:f 3735:a 3728:a 3724:n 3720:n 3714:. 3707:c 3701:a 3697:b 3687:a 3662:) 3659:2 3652:( 3634:n 3622:2 3618:1 3615:+ 3612:n 3609:3 3599:0 3593:n 3581:2 3578:n 3570:{ 3565:= 3562:) 3559:n 3556:( 3553:f 3533:a 3529:f 3523:a 3521:9 3515:a 3509:f 3503:a 3501:3 3495:a 3493:4 3489:b 3485:a 3481:a 3475:a 3473:3 3469:k 3461:b 3455:a 3453:3 3447:a 3445:2 3439:a 3437:3 3431:a 3429:2 3425:c 3421:b 3417:k 3413:f 3409:d 3404:d 3400:a 3398:3 3393:b 3389:a 3385:n 3380:k 3376:f 3369:2 3365:n 3361:m 3357:k 3353:n 3349:m 3345:) 3343:n 3341:( 3339:f 3327:2 3324:/ 3320:n 3307:2 3304:/ 3299:n 3297:3 3286:) 3283:i 3279:a 3277:( 3275:f 3269:i 3265:a 3259:n 3255:0 3252:a 3247:) 3244:i 3242:a 3237:i 3235:p 3230:n 3224:n 3216:n 3194:. 3190:) 3187:2 3180:( 3168:1 3162:n 3150:2 3146:1 3143:+ 3140:n 3137:3 3127:0 3121:n 3109:2 3106:n 3098:{ 3093:= 3090:) 3087:n 3084:( 3081:f 3061:1 3058:1 3048:1 3038:1 3033:0 3028:1 3023:0 3018:1 2995:0 2986:n 2982:n 2978:n 2976:2 2967:n 2965:2 2961:1 2953:1 2929:s 2925:s 2917:3 2914:/ 2911:1 2899:n 2891:3 2888:/ 2885:1 2875:h 2871:w 2865:1 2862:w 2856:k 2852:w 2848:k 2844:w 2836:n 2826:n 2824:( 2822:f 2817:k 2813:n 2805:f 2796:β€² 2793:n 2784:) 2782:β€² 2779:n 2777:( 2775:H 2768:n 2764:β€² 2761:n 2752:) 2750:β€² 2747:n 2745:( 2743:H 2739:/ 2735:β€² 2732:n 2721:n 2719:3 2710:n 2700:3 2697:/ 2692:n 2690:2 2677:2 2674:/ 2669:n 2667:3 2657:n 2652:n 2636:. 2632:) 2629:3 2622:( 2610:2 2604:n 2593:} 2587:3 2583:1 2577:n 2574:2 2568:, 2565:n 2562:2 2558:{ 2550:1 2547:, 2544:0 2538:n 2528:} 2525:n 2522:2 2519:{ 2513:{ 2508:= 2505:) 2502:n 2499:( 2496:R 2482:2 2479:/ 2474:n 2472:3 2464:f 2458:n 2456:3 2445:f 2435:n 2425:3 2422:/ 2417:n 2406:n 2404:3 2396:n 2391:n 2375:. 2371:) 2368:6 2361:( 2349:4 2343:n 2332:} 2326:3 2322:1 2316:n 2310:, 2307:n 2304:2 2300:{ 2292:5 2289:, 2286:3 2283:, 2280:2 2277:, 2274:1 2271:, 2268:0 2262:n 2252:} 2249:n 2246:2 2243:{ 2237:{ 2232:= 2229:) 2226:n 2223:( 2220:R 2165:k 2158:k 2153:k 2147:k 2142:k 2125:k 2120:k 2112:k 2098:/ 2074:b 2069:c 2065:b 2061:a 2047:c 2041:+ 2038:b 2032:+ 2029:a 2023:= 2020:p 2010:p 1995:( 1964:2 1957:3 1905:0 1902:a 1897:q 1895:a 1893:( 1891:f 1885:2 1882:a 1878:1 1875:a 1873:( 1871:f 1865:1 1862:a 1858:0 1855:a 1853:( 1851:f 1846:) 1843:q 1841:a 1837:1 1834:a 1830:0 1827:a 1825:( 1800:. 1796:) 1793:2 1786:( 1781:1 1775:n 1763:2 1759:1 1756:+ 1753:n 1750:3 1740:, 1736:) 1733:2 1726:( 1721:0 1715:n 1703:2 1700:n 1692:{ 1687:= 1684:) 1681:n 1678:( 1675:f 1657:x 1652:x 1583:4 1580:/ 1577:3 1567:4 1564:/ 1561:3 1517:Γ— 1469:y 1455:) 1451:x 1444:Γ— 1438:x 1434:y 1430:y 1426:x 1393:n 1389:2 1369:9 1356:9 1350:) 1297:9 1258:8 1216:) 1199:n 1193:) 1131:1 1125:5 875:n 865:n 856:f 849:n 819:. 815:) 812:2 805:( 800:1 794:n 782:2 778:1 775:+ 772:n 769:3 759:, 755:) 752:2 745:( 740:0 734:n 722:2 719:n 711:{ 706:= 703:) 700:n 697:( 694:f 684:n 678:n 676:3 667:n 662:n 655:k 651:i 647:n 636:k 634:a 629:k 625:n 616:0 613:a 608:i 606:a 601:i 580:1 577:= 572:i 568:a 547:i 527:n 511:) 509:n 505:f 500:i 498:a 493:i 489:n 485:f 479:i 477:a 455:0 449:i 439:) 434:1 428:i 424:a 420:( 417:f 410:, 407:0 404:= 401:i 391:n 385:{ 380:= 375:i 371:a 338:. 334:) 331:2 324:( 319:1 313:n 303:1 300:+ 297:n 294:3 287:, 283:) 280:2 273:( 268:0 262:n 252:2 248:/ 244:n 238:{ 233:= 230:) 227:n 224:( 221:f 211:f 165:y 161:x 149:y 145:x 97:Γ— 36:: 20:)

Index

Collatz sequence
(more unsolved problems in mathematics)

Directed graph
orbits
unsolved problems in mathematics
positive integer
sequences of integers
even
Lothar Collatz
hailstones
Paul ErdΕ‘s
Jeffrey Lagarias




Total Stopping Time: numbers up to 250, 1000, 4000, 20000, 100000, 500000
positive integer
modular arithmetic
function
A008884
OEIS

A006877
OEIS
maximum
A006884
OEIS
A006577

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