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Happy number

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44: 5333: 2384:
392, 397, 404, 409, 440, 446, 464, 469, 478, 487, 490, 496, 536, 556, 563, 565, 566, 608, 617, 622, 623, 632, 635, 637, 638, 644, 649, 653, 655, 656, 665, 671, 673, 680, 683, 694, 700, 709, 716, 736, 739, 748, 761, 763, 784, 790, 793, 802, 806, 818, 820, 833, 836, 847, 860, 863, 874, 881, 888, 899, 901, 904, 907, 910, 912, 913, 921, 923, 931, 932, 937, 940, 946, 964, 970, 973, 989, 998, 1000 (sequence
2266:
1, 6, 36, 44, 49, 79, 100, 160, 170, 216, 224, 229, 254, 264, 275, 285, 289, 294, 335, 347, 355, 357, 388, 405, 415, 417, 439, 460, 469, 474, 533, 538, 580, 593, 600, 608, 628, 638, 647, 695, 707, 715, 717, 767, 777, 787, 835, 837, 847, 880, 890, 928, 940, 953, 960, 968, 1010, 1018, 1020, 1033, 1058,
2642:
11031, 1233E, 13011, 1332E, 16377, 17367, 17637, 22E8E, 2331E, 233E1, 23955, 25935, 25X8E, 28X5E, 28XE5, 2X8E5, 2E82E, 2E8X5, 31011, 31101, 3123E, 3132E, 31677, 33E21, 35295, 35567, 35765, 35925, 36557, 37167, 37671, 39525, 4878E, 4X7X7, 53567, 55367, 55637, 56357, 57635, 58XX5, 5X82E, 5XX85, 606EE,
2383:
1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97, 100, 103, 109, 129, 130, 133, 139, 167, 176, 188, 190, 192, 193, 203, 208, 219, 226, 230, 236, 239, 262, 263, 280, 291, 293, 301, 302, 310, 313, 319, 320, 326, 329, 331, 338, 356, 362, 365, 367, 368, 376, 379, 383, 386, 391,
2643:
63575, 63771, 66E0E, 67317, 67371, 67535, 6E60E, 71367, 71637, 73167, 76137, 7XX47, 82XE5, 82EX5, 8487E, 848E7, 84E87, 8874E, 8X1X7, 8X25E, 8X2E5, 8X5X5, 8XX17, 8XX71, 8E2X5, 8E847, 92355, 93255, 93525, 95235, X1X87, X258E, X285E, X2E85, X85X5, X8X17, XX477, XX585, E228E, E606E, E822E, EX825, ...
594: 2416:
The first pair of consecutive 10-happy numbers is 31 and 32. The first set of three consecutive is 1880, 1881, and 1882. It has been proven that there exist sequences of consecutive happy numbers of any natural number length. The beginning of the first run of at least
2376:, all numbers either lead to 1 and are happy, or lead to the cycle and are unhappy. Because base 10 has no other perfect digital invariants except for 1, no positive integer other than 1 is the sum of the squares of its own digits. 2259:, all numbers either lead to 1 and are happy, or lead to the cycle and are unhappy. Because base 6 has no other perfect digital invariants except for 1, no positive integer other than 1 is the sum of the squares of its own digits. 2445:
3, 20, 143, 1442, 14377, 143071, 1418854, 14255667, 145674808, 1492609148, 15091199357, 149121303586, 1443278000870, 13770853279685, 130660965862333, 1245219117260664, 12024696404768025, 118226055080025491, 1183229962059381238,
2433:
As Robert Styer puts it in his paper calculating this series: "Amazingly, the same value of N that begins the least sequence of six consecutive happy numbers also begins the least sequence of seven consecutive happy numbers."
1623: 1766: 1467: 430: 1326: 1945:
of around 0.15. Perhaps surprisingly, then, the 10-happy numbers do not have an asymptotic density. The upper density of the happy numbers is greater than 0.18577, and the lower density is less than 0.1138.
1205: 1097: 989: 3435: 2519:-happy prime will not necessarily create another happy prime. For instance, while 19 is a 10-happy prime, 91 = 13 Ă— 7 is not prime (but is still 10-happy). 737: 228: 103: 274: 149: 775: 6137: 182: 2374: 2333: 2257: 2216: 2145: 2108: 889: 832: 1883: 624: 1856: 2702: 2300: 5369: 2676: 2183: 2075: 366: 5740: 2517: 2493: 2473: 2016: 1996: 1923: 1903: 1829: 1809: 1789: 909: 852: 795: 684: 664: 644: 419: 336: 305: 2704:
described in the definition of happy given at the top of this article, repeatedly; after each time, they check for both halt conditions: reaching 1, and
2638:, there are no 12-happy primes less than 10000, the first 12-happy primes are (the letters X and E represent the decimal numbers 10 and 11 respectively) 276:, the number that started the sequence, and so the process continues in an infinite cycle without ever reaching 1. A number which is not happy is called 1473: 6643: 3246: 3187: 3129: 3096: 3071: 2570: 2409: 2391: 5822: 3428: 2402:
1, 7, 13, 19, 23, 28, 44, 49, 68, 79, 129, 133, 139, 167, 188, 226, 236, 239, 338, 356, 367, 368, 379, 446, 469, 478, 556, 566, 888, 899. (sequence
1972: 2398:
The distinct combinations of digits that form 10-happy numbers below 1000 are (the rest are just rearrangements and/or insertions of zero digits):
5745: 1629: 1337: 5659: 3336: 589:{\displaystyle F_{p,b}(n)=\sum _{i=0}^{\lfloor \log _{b}{n}\rfloor }{\left({\frac {n{\bmod {b^{i+1}}}-n{\bmod {b^{i}}}}{b^{i}}}\right)}^{p}} 4235: 3421: 1211: 59:
is a number which eventually reaches 1 when replaced by the sum of the square of each digit. For instance, 13 is a happy number because
5362: 4230: 4245: 4225: 3319: 1103: 995: 5996: 4938: 4518: 6077: 4240: 5024: 3386: 5355: 3378: 2712: 6199: 5857: 4340: 6638: 4690: 4009: 3802: 3208: 6224: 4725: 4695: 4370: 4360: 5690: 4866: 4280: 4014: 3994: 3363: 4556: 4720: 2563:
7, 13, 19, 23, 31, 79, 97, 103, 109, 139, 167, 193, 239, 263, 293, 313, 331, 367, 379, 383, 397, 409, 487 (sequence
6132: 4815: 4438: 4195: 4004: 3986: 3880: 3870: 3860: 4700: 4943: 4488: 4109: 3895: 3890: 3885: 3875: 3852: 2982: 1929:
of a number is preserved by removing or inserting zeroes at will, since they do not contribute to the cross sum.
920: 422: 396: 339: 3928: 4185: 5765: 5054: 5019: 4805: 4715: 4589: 4564: 4473: 4463: 4075: 4057: 3977: 6282: 5411: 5314: 4584: 4458: 4089: 3865: 3645: 3572: 3217: 6619: 6209: 5862: 5770: 4569: 4423: 4350: 3505: 5278: 4918: 689: 383:) by his daughter, who had learned of them at school. However, they "may have originated in Russia" ( 6189: 5211: 5105: 5069: 4810: 4533: 4513: 4330: 3999: 3787: 3759: 3043: 187: 62: 6184: 5842: 4933: 4797: 4792: 4760: 4523: 4498: 4493: 4468: 4398: 4394: 4325: 4215: 4047: 3843: 3812: 2962: 2110:
is the trivial perfect digital invariant 1, and there are no other cycles. Because all numbers are
233: 108: 5332: 6292: 6229: 6219: 6204: 5837: 5695: 5336: 5090: 5085: 4999: 4973: 4871: 4850: 4622: 4503: 4453: 4375: 4345: 4285: 4052: 4032: 3963: 3676: 3153: 3033: 742: 372: 5616: 4220: 3203: 6261: 6236: 6214: 6194: 5817: 5789: 5482: 5230: 5175: 5029: 5004: 4978: 4755: 4433: 4428: 4355: 4335: 4320: 4042: 4024: 3943: 3933: 3918: 3696: 3681: 3343: 3315: 2578: 798: 154: 2346: 2305: 2229: 2188: 2117: 2080: 861: 804: 6171: 6161: 6156: 6093: 5940: 5807: 5710: 5266: 5059: 4645: 4617: 4607: 4599: 4483: 4448: 4443: 4410: 4104: 4067: 3958: 3953: 3948: 3938: 3910: 3797: 3749: 3744: 3701: 3640: 2967: 1861: 603: 380: 376: 1834: 5872: 5832: 5715: 5680: 5644: 5599: 5452: 5440: 5242: 5131: 5064: 4990: 4913: 4887: 4705: 4418: 4275: 4210: 4180: 4170: 4165: 3831: 3739: 3686: 3530: 3470: 3367: 3311: 2705: 2681: 2279: 1942: 371:
The origin of happy numbers is not clear. Happy numbers were brought to the attention of
2655: 2335:
is the trivial perfect digital invariant 1, and the only cycle is the eight-number cycle
2218:
is the trivial perfect digital invariant 1, and the only cycle is the eight-number cycle
2162: 2054: 345: 3047: 2861:"""Determine if the specified number is a happy number.""" 6277: 6251: 6148: 6016: 5867: 5827: 5812: 5684: 5575: 5540: 5495: 5420: 5402: 5247: 5115: 5100: 4964: 4928: 4903: 4779: 4750: 4735: 4612: 4508: 4478: 4205: 4160: 4037: 3635: 3630: 3625: 3597: 3582: 3495: 3480: 3458: 3445: 3303: 2972: 2613: 2502: 2478: 2458: 2111: 2001: 1981: 1941:
By inspection of the first million or so 10-happy numbers, it appears that they have a
1908: 1888: 1814: 1794: 1774: 894: 837: 780: 669: 649: 629: 404: 321: 312: 290: 31: 3372: 6632: 6287: 6052: 5916: 5889: 5725: 5590: 5528: 5519: 5504: 5467: 5393: 5170: 5154: 5095: 5049: 4745: 4730: 4640: 4365: 3923: 3792: 3754: 3711: 3592: 3577: 3567: 3525: 3515: 3490: 52: 43: 6608: 6603: 6598: 6593: 6588: 6583: 6578: 6573: 6568: 6563: 6558: 6553: 6548: 6543: 6538: 6533: 6528: 6523: 6518: 6513: 6508: 6503: 6498: 6493: 6488: 6483: 6478: 6473: 6468: 6463: 6458: 6453: 6448: 6443: 6438: 6241: 5964: 5730: 5720: 5705: 5700: 5664: 5378: 5206: 5195: 5110: 4923: 4840: 4740: 4710: 4685: 4669: 4574: 4541: 4290: 4264: 4175: 4114: 3691: 3587: 3520: 3500: 3475: 2977: 2609:= 176, which is a 10-happy number. Paul Jobling discovered the prime in 2005. 2496: 2429:
1, 31, 1880, 7839, 44488, 7899999999999959999999996, 7899999999999959999999996, ...
3346: 3281: 3262: 1618:{\displaystyle F_{2,6}^{2}(347)=F_{2,6}(44)=F_{2,6}(112_{6})=1^{2}+1^{2}+2^{2}=6} 6433: 6428: 6423: 6418: 6413: 6408: 6403: 6398: 6393: 6388: 6383: 6378: 6373: 6368: 6363: 6358: 6353: 6348: 6343: 6338: 6333: 6179: 5852: 5760: 5755: 5735: 5649: 5552: 5428: 5165: 5040: 4845: 4309: 4200: 4155: 4150: 3900: 3807: 3706: 3535: 3510: 3485: 3398: 3394: 3236: 3173: 3119: 3086: 3061: 316: 151:. On the other hand, 4 is not a happy number because the sequence starting with 2605:
digits because the many 0s do not contribute to the sum of squared digits, and
6256: 6072: 5980: 5900: 5750: 5654: 5302: 5283: 4579: 4190: 3002: 3413: 6297: 6246: 6127: 4908: 4835: 4827: 4632: 4546: 3664: 3351: 3124:"Sequence A072494 (First of triples of consecutive happy numbers)" 2267:
1125, 1135, 1137, 1168, 1178, 1187, 1195, 1197, 1207, 1238, 1277, 1292, 1295
2262:
In base 10, the 74 6-happy numbers up to 1296 = 6 are (written in base 10):
3360: 17: 5009: 3091:"Sequence A035502 (Lower of pair of consecutive happy numbers)" 1761:{\displaystyle F_{2,6}^{3}(347)=F_{2,6}(6)=F_{2,6}(10_{6})=1^{2}+0^{2}=1} 1462:{\displaystyle F_{2,6}(347)=F_{2,6}(1335_{6})=1^{2}+3^{2}+3^{2}+5^{2}=44} 2652:
The examples below implement the perfect digital invariant function for
5799: 5347: 5014: 4673: 2753:"""Perfect digital invariant function.""" 2635: 2556: 1953: 47:
Tree showing all happy numbers up to 100, with 130 seen with 13 and 31.
3158: 2539: 2527: 2523: 2148: 2031: 2027: 1966: 1962: 2612:
As of 2010, the largest known 10-happy prime is 2 âˆ’ 1 (a
5794: 5780: 3038: 1321:{\displaystyle F_{2,10}^{4}(19)=F_{2,10}(100)=1^{2}+0^{2}+0^{2}=1} 42: 3241:"Sequence A068571 (Number of happy numbers <= 10^n)" 3178:"Sequence A055629 (Beginning of first run of at least 3066:"Sequence A161872 (Smallest unhappy number in base n)" 5351: 5300: 5264: 5228: 5192: 5152: 4777: 4666: 4392: 4307: 4262: 4139: 3829: 3776: 3728: 3662: 3614: 3552: 3456: 3417: 2546:
211, 1021, 1335, 2011, 2425, 2555, 3351, 4225, 4441, 5255, 5525
1200:{\displaystyle F_{2,10}^{3}(19)=F_{2,10}(68)=6^{2}+8^{2}=100} 546: 517: 27:
Numbers with a certain property involving recursive summation
1092:{\displaystyle F_{2,10}^{2}(19)=F_{2,10}(82)=8^{2}+2^{2}=68} 3240: 3204:"Smallest Examples of Strings of Consecutive Happy Numbers" 3177: 3123: 3090: 3065: 2565: 2404: 2386: 3024:
Gilmer, Justin (2013). "On the Density of Happy Numbers".
2437:
The number of 10-happy numbers up to 10 for 1 â‰€ 
6328: 6323: 6318: 6313: 3223: 2684: 2658: 2522:
All prime numbers are 2-happy and 4-happy primes, as
2505: 2481: 2461: 2379:
In base 10, the 143 10-happy numbers up to 1000 are:
2349: 2308: 2282: 2232: 2191: 2165: 2120: 2083: 2057: 2004: 1984: 1911: 1891: 1864: 1837: 1817: 1797: 1777: 1632: 1476: 1340: 1214: 1106: 998: 923: 897: 864: 840: 807: 783: 745: 692: 672: 652: 632: 606: 433: 407: 348: 324: 293: 236: 190: 157: 111: 65: 2499:. Unlike happy numbers, rearranging the digits of a 2147:, all numbers lead to 1 and are happy. As a result, 6306: 6270: 6170: 6147: 6121: 5888: 5881: 5779: 5673: 5637: 5386: 5124: 5078: 5038: 4989: 4963: 4896: 4880: 4859: 4826: 4791: 4631: 4598: 4555: 4532: 4409: 4097: 4088: 4066: 4023: 3985: 3976: 3909: 3851: 3842: 2343:and because all numbers are preperiodic points for 2226:and because all numbers are preperiodic points for 2696: 2670: 2511: 2487: 2467: 2368: 2327: 2302:, the only positive perfect digital invariant for 2294: 2251: 2210: 2185:, the only positive perfect digital invariant for 2177: 2139: 2102: 2077:, the only positive perfect digital invariant for 2069: 2010: 1990: 1917: 1897: 1877: 1850: 1823: 1803: 1783: 1760: 1617: 1461: 1320: 1199: 1091: 983: 903: 883: 846: 826: 789: 769: 731: 678: 658: 638: 618: 588: 413: 360: 330: 299: 268: 222: 176: 143: 97: 338:that eventually reaches 1 when iterated over the 6010: = 0, 1, 2, 3, ... 2339:4 → 16 → 37 → 58 → 89 → 145 → 42 → 20 → 4 → ... 2222:5 → 41 → 25 → 45 → 105 → 42 → 32 → 21 → 5 → ... 2018:-happy. The only happy integer bases less than 3152:Pan, Hao (2006). "Consecutive Happy Numbers". 855: 5363: 3429: 8: 499: 478: 391:Happy numbers and perfect digital invariants 3263:"The Prime Database: 10 + 7426247 · 10 + 1" 984:{\displaystyle F_{2,10}(19)=1^{2}+9^{2}=82} 5885: 5370: 5356: 5348: 5297: 5261: 5225: 5189: 5149: 4823: 4788: 4774: 4663: 4406: 4389: 4304: 4259: 4136: 4094: 3982: 3848: 3839: 3826: 3773: 3730:Possessing a specific set of other numbers 3725: 3659: 3611: 3549: 3453: 3436: 3422: 3414: 3247:On-Line Encyclopedia of Integer Sequences 3188:On-Line Encyclopedia of Integer Sequences 3157: 3130:On-Line Encyclopedia of Integer Sequences 3097:On-Line Encyclopedia of Integer Sequences 3072:On-Line Encyclopedia of Integer Sequences 3037: 2683: 2657: 2504: 2480: 2460: 2354: 2348: 2313: 2307: 2281: 2237: 2231: 2196: 2190: 2164: 2125: 2119: 2088: 2082: 2056: 2003: 1983: 1910: 1890: 1869: 1863: 1842: 1836: 1816: 1796: 1776: 1746: 1733: 1717: 1698: 1670: 1648: 1637: 1631: 1603: 1590: 1577: 1561: 1542: 1514: 1492: 1481: 1475: 1447: 1434: 1421: 1408: 1392: 1373: 1345: 1339: 1306: 1293: 1280: 1252: 1230: 1219: 1213: 1185: 1172: 1144: 1122: 1111: 1105: 1077: 1064: 1036: 1014: 1003: 997: 969: 956: 928: 922: 896: 869: 863: 839: 812: 806: 782: 761: 750: 744: 708: 697: 691: 671: 651: 631: 605: 580: 567: 554: 549: 545: 525: 520: 516: 510: 505: 494: 485: 477: 466: 438: 432: 406: 375:(a British author and senior lecturer in 347: 323: 292: 254: 241: 235: 208: 195: 189: 162: 156: 129: 116: 110: 83: 70: 64: 2542:, the 6-happy primes below 1296 = 6 are 2994: 1973:(more unsolved problems in mathematics) 2475:-happy prime is a number that is both 854:-unhappy otherwise. If a number is a 7: 2559:, the 10-happy primes below 500 are 856:nontrivial perfect digital invariant 384: 3308:Unsolved Problems in Number Theory 423:perfect digital invariant function 340:perfect digital invariant function 25: 5847: 2607:1 + 7 + 4 + 2 + 6 + 2 + 4 + 7 + 1 2421:consecutive 10-happy numbers for 6644:Base-dependent integer sequences 5746:Supersingular (moonshine theory) 5331: 4939:Perfect digit-to-digit invariant 1925:-happy, since its sum is 1. The 1331:For example, 347 is 6-happy, as 914:For example, 19 is 10-happy, as 732:{\displaystyle F_{2,b}^{j}(n)=1} 2715:to check if a number is happy: 1956:Unsolved problem in mathematics 421:be a natural number. Given the 5741:Supersingular (elliptic curve) 3361:calculate if a number is happy 2425: = 1, 2, 3, ... is 1978:A happy base is a number base 1969:the only bases that are happy? 1723: 1710: 1688: 1682: 1660: 1654: 1567: 1554: 1532: 1526: 1504: 1498: 1398: 1385: 1363: 1357: 1270: 1264: 1242: 1236: 1162: 1156: 1134: 1128: 1054: 1048: 1026: 1020: 946: 940: 720: 714: 456: 450: 223:{\displaystyle 1^{2}+6^{2}=37} 98:{\displaystyle 1^{2}+3^{2}=10} 1: 5522:2 Â± 2 Â± 1 3778:Expressible via specific sums 2616:). Its decimal expansion has 1811:-happy number, and for every 269:{\displaystyle 2^{2}+0^{2}=4} 144:{\displaystyle 1^{2}+0^{2}=1} 3209:Journal of Integer Sequences 4867:Multiplicative digital root 3282:"The Prime Database: 2 − 1" 3182:consecutive happy numbers)" 770:{\displaystyle F_{2,b}^{j}} 6660: 3237:Sloane, N. J. A. 3174:Sloane, N. J. A. 3120:Sloane, N. J. A. 3087:Sloane, N. J. A. 3062:Sloane, N. J. A. 1791:-happy numbers, as 1 is a 1771:There are infinitely many 394: 29: 6617: 5327: 5310: 5296: 5274: 5260: 5238: 5224: 5202: 5188: 5161: 5148: 4944:Perfect digital invariant 4787: 4773: 4681: 4662: 4519:Superior highly composite 4405: 4388: 4316: 4303: 4271: 4258: 4146: 4135: 3838: 3825: 3783: 3772: 3735: 3724: 3672: 3658: 3621: 3610: 3563: 3548: 3466: 3452: 2983:Perfect digital invariant 2598:is a 10-happy prime with 666:-happy if there exists a 397:Perfect digital invariant 6128:Mega (1,000,000+ digits) 5997:Arithmetic progression ( 4557:Euler's totient function 4341:Euler–Jacobi pseudoprime 3616:Other polynomial numbers 3216:: 5. 10.6.3 – via 2717: 177:{\displaystyle 4^{2}=16} 30:Not to be confused with 4371:Somer–Lucas pseudoprime 4361:Lucas–Carmichael number 4196:Lazy caterer's sequence 3366:25 January 2019 at the 3337:Mathews: Happy Numbers. 3005:. Wolfram Research, Inc 2369:{\displaystyle F_{2,b}} 2328:{\displaystyle F_{2,b}} 2252:{\displaystyle F_{2,b}} 2211:{\displaystyle F_{2,b}} 2140:{\displaystyle F_{2,b}} 2103:{\displaystyle F_{2,b}} 884:{\displaystyle F_{2,b}} 827:{\displaystyle F_{2,b}} 34:(derived from Sanskrit 6283:Industrial-grade prime 5660:Newman–Shanks–Williams 4246:Wedderburn–Etherington 3646:Lucky numbers of Euler 3218:University of Waterloo 3202:Styer, Robert (2010). 2698: 2672: 2513: 2489: 2469: 2370: 2329: 2296: 2253: 2212: 2179: 2141: 2104: 2071: 2012: 1998:where every number is 1992: 1919: 1899: 1879: 1878:{\displaystyle 10^{n}} 1852: 1825: 1805: 1785: 1762: 1619: 1463: 1322: 1201: 1093: 985: 905: 885: 848: 828: 791: 771: 733: 680: 660: 640: 620: 619:{\displaystyle b>1} 590: 503: 415: 362: 332: 301: 270: 224: 178: 145: 99: 48: 6620:List of prime numbers 6078:Sophie Germain/Safe ( 4534:Prime omega functions 4351:Frobenius pseudoprime 4141:Combinatorial numbers 4010:Centered dodecahedral 3803:Primary pseudoperfect 3387:"7 and Happy Numbers" 3379:145 and the Melancoil 2699: 2673: 2514: 2490: 2470: 2446:12005034444292997294. 2371: 2330: 2297: 2254: 2213: 2180: 2142: 2105: 2072: 2013: 1993: 1920: 1900: 1880: 1853: 1851:{\displaystyle b^{n}} 1826: 1806: 1786: 1763: 1620: 1464: 1323: 1202: 1094: 986: 906: 886: 849: 829: 792: 772: 734: 681: 661: 641: 621: 591: 462: 416: 363: 333: 302: 271: 225: 179: 146: 100: 46: 38:meaning "great joy"). 5802:(10 âˆ’ 1)/9 4993:-composition related 4793:Arithmetic functions 4395:Arithmetic functions 4331:Elliptic pseudoprime 4015:Centered icosahedral 3995:Centered tetrahedral 2697:{\displaystyle b=10} 2682: 2656: 2503: 2479: 2459: 2347: 2306: 2295:{\displaystyle b=10} 2280: 2230: 2189: 2163: 2118: 2081: 2055: 2002: 1982: 1909: 1889: 1862: 1835: 1815: 1795: 1775: 1630: 1474: 1338: 1212: 1104: 996: 921: 895: 862: 838: 805: 781: 743: 690: 670: 650: 630: 604: 431: 405: 346: 322: 291: 234: 188: 155: 109: 63: 6639:Arithmetic dynamics 6111: Â± 7, ... 5638:By integer sequence 5423:(2 + 1)/3 4919:Kaprekar's constant 4439:Colossally abundant 4326:Catalan pseudoprime 4226:Schröder–Hipparchus 4005:Centered octahedral 3881:Centered heptagonal 3871:Centered pentagonal 3861:Centered triangular 3461:and related numbers 3335:Schneider, Walter: 3280:Chris K. Caldwell. 3261:Chris K. Caldwell. 3048:2011arXiv1110.3836G 2963:Arithmetic dynamics 2678:and a default base 2671:{\displaystyle p=2} 2648:Programming example 2441: â‰€ 20 is 2178:{\displaystyle b=6} 2070:{\displaystyle b=4} 1933:Natural density of 1653: 1497: 1235: 1127: 1019: 766: 713: 361:{\displaystyle p=2} 230:eventually reaches 6293:Formula for primes 5926: + 2 or 5858:Smarandache–Wellin 5337:Mathematics portal 5279:Aronson's sequence 5025:Smarandache–Wellin 4782:-dependent numbers 4489:Primitive abundant 4376:Strong pseudoprime 4366:Perrin pseudoprime 4346:Fermat pseudoprime 4286:Wolstenholme prime 4110:Squared triangular 3896:Centered decagonal 3891:Centered nonagonal 3886:Centered octagonal 3876:Centered hexagonal 3401:on 15 January 2018 3375:at The Math Forum. 3344:Weisstein, Eric W. 3250:. OEIS Foundation. 3191:. OEIS Foundation. 3075:. OEIS Foundation. 2706:repeating a number 2694: 2668: 2509: 2485: 2465: 2366: 2325: 2292: 2249: 2208: 2175: 2137: 2112:preperiodic points 2100: 2067: 2008: 1988: 1915: 1895: 1875: 1848: 1821: 1801: 1781: 1758: 1633: 1615: 1477: 1459: 1318: 1215: 1197: 1107: 1089: 999: 981: 901: 881: 844: 824: 787: 767: 746: 729: 693: 676: 656: 636: 616: 586: 411: 358: 328: 297: 287:More generally, a 266: 220: 174: 141: 95: 49: 6626: 6625: 6237:Carmichael number 6172:Composite numbers 6107: Â± 3, 8 6103: Â± 1, 4 6066: Â± 1, 
 6062: Â± 1, 4 6058: Â± 1, 2 6048: 6047: 5593:3·2 âˆ’ 1 5498:2·3 + 1 5412:Double Mersenne ( 5345: 5344: 5323: 5322: 5292: 5291: 5256: 5255: 5220: 5219: 5184: 5183: 5144: 5143: 5140: 5139: 4959: 4958: 4769: 4768: 4658: 4657: 4654: 4653: 4600:Aliquot sequences 4411:Divisor functions 4384: 4383: 4356:Lucas pseudoprime 4336:Euler pseudoprime 4321:Carmichael number 4299: 4298: 4254: 4253: 4131: 4130: 4127: 4126: 4123: 4122: 4084: 4083: 3972: 3971: 3929:Square triangular 3821: 3820: 3768: 3767: 3720: 3719: 3654: 3653: 3606: 3605: 3544: 3543: 3133:. OEIS Foundation 3100:. OEIS Foundation 2711:A simple test in 2579:palindromic prime 2530:are happy bases. 2512:{\displaystyle b} 2488:{\displaystyle b} 2468:{\displaystyle b} 2151:is a happy base. 2011:{\displaystyle b} 1991:{\displaystyle b} 1918:{\displaystyle b} 1898:{\displaystyle b} 1824:{\displaystyle n} 1804:{\displaystyle b} 1784:{\displaystyle b} 904:{\displaystyle b} 847:{\displaystyle b} 790:{\displaystyle j} 679:{\displaystyle j} 659:{\displaystyle b} 639:{\displaystyle n} 573: 414:{\displaystyle n} 331:{\displaystyle b} 300:{\displaystyle b} 16:(Redirected from 6651: 6157:Eisenstein prime 6112: 6088: 6067: 6039: 6011: 5991: 5975: 5959: 5954: + 6, 5950: + 2, 5935: 5930: + 4, 5911: 5886: 5803: 5766:Highly cototient 5628: 5627: 5621: 5611: 5594: 5585: 5570: 5547: 5546:·2 âˆ’ 1 5535: 5534:·2 + 1 5523: 5514: 5499: 5490: 5477: 5462: 5447: 5435: 5434:·2 + 1 5424: 5415: 5406: 5397: 5372: 5365: 5358: 5349: 5335: 5298: 5267:Natural language 5262: 5226: 5194:Generated via a 5190: 5150: 5055:Digit-reassembly 5020:Self-descriptive 4824: 4789: 4775: 4726:Lucas–Carmichael 4716:Harmonic divisor 4664: 4590:Sparsely totient 4565:Highly cototient 4474:Multiply perfect 4464:Highly composite 4407: 4390: 4305: 4260: 4241:Telephone number 4137: 4095: 4076:Square pyramidal 4058:Stella octangula 3983: 3849: 3840: 3832:Figurate numbers 3827: 3774: 3726: 3660: 3612: 3550: 3454: 3438: 3431: 3424: 3415: 3410: 3408: 3406: 3397:. Archived from 3357: 3356: 3325: 3310:(3rd ed.). 3290: 3289: 3277: 3271: 3270: 3258: 3252: 3251: 3233: 3227: 3224:Sloane "A055629" 3221: 3199: 3193: 3192: 3170: 3164: 3163: 3161: 3149: 3143: 3142: 3140: 3138: 3116: 3110: 3109: 3107: 3105: 3083: 3077: 3076: 3058: 3052: 3051: 3041: 3021: 3015: 3014: 3012: 3010: 2999: 2968:Fortunate number 2952: 2949: 2946: 2943: 2940: 2937: 2934: 2931: 2928: 2925: 2922: 2919: 2916: 2913: 2910: 2907: 2904: 2901: 2898: 2895: 2892: 2889: 2886: 2883: 2880: 2877: 2874: 2871: 2868: 2865: 2862: 2859: 2856: 2853: 2850: 2847: 2844: 2841: 2838: 2835: 2832: 2829: 2826: 2823: 2820: 2817: 2814: 2811: 2808: 2805: 2802: 2799: 2796: 2793: 2790: 2787: 2784: 2781: 2778: 2775: 2772: 2769: 2766: 2763: 2760: 2757: 2754: 2751: 2748: 2745: 2742: 2739: 2736: 2733: 2730: 2727: 2724: 2721: 2703: 2701: 2700: 2695: 2677: 2675: 2674: 2669: 2625: 2624: 2621: 2608: 2604: 2603: 2597: 2595: 2593: 2590: 2587: 2568: 2518: 2516: 2515: 2510: 2494: 2492: 2491: 2486: 2474: 2472: 2471: 2466: 2407: 2389: 2375: 2373: 2372: 2367: 2365: 2364: 2334: 2332: 2331: 2326: 2324: 2323: 2301: 2299: 2298: 2293: 2272:10-happy numbers 2258: 2256: 2255: 2250: 2248: 2247: 2217: 2215: 2214: 2209: 2207: 2206: 2184: 2182: 2181: 2176: 2146: 2144: 2143: 2138: 2136: 2135: 2109: 2107: 2106: 2101: 2099: 2098: 2076: 2074: 2073: 2068: 2025: 2023: 2017: 2015: 2014: 2009: 1997: 1995: 1994: 1989: 1957: 1924: 1922: 1921: 1916: 1904: 1902: 1901: 1896: 1884: 1882: 1881: 1876: 1874: 1873: 1857: 1855: 1854: 1849: 1847: 1846: 1830: 1828: 1827: 1822: 1810: 1808: 1807: 1802: 1790: 1788: 1787: 1782: 1767: 1765: 1764: 1759: 1751: 1750: 1738: 1737: 1722: 1721: 1709: 1708: 1681: 1680: 1652: 1647: 1624: 1622: 1621: 1616: 1608: 1607: 1595: 1594: 1582: 1581: 1566: 1565: 1553: 1552: 1525: 1524: 1496: 1491: 1468: 1466: 1465: 1460: 1452: 1451: 1439: 1438: 1426: 1425: 1413: 1412: 1397: 1396: 1384: 1383: 1356: 1355: 1327: 1325: 1324: 1319: 1311: 1310: 1298: 1297: 1285: 1284: 1263: 1262: 1234: 1229: 1206: 1204: 1203: 1198: 1190: 1189: 1177: 1176: 1155: 1154: 1126: 1121: 1098: 1096: 1095: 1090: 1082: 1081: 1069: 1068: 1047: 1046: 1018: 1013: 990: 988: 987: 982: 974: 973: 961: 960: 939: 938: 910: 908: 907: 902: 890: 888: 887: 882: 880: 879: 853: 851: 850: 845: 833: 831: 830: 825: 823: 822: 796: 794: 793: 788: 776: 774: 773: 768: 765: 760: 738: 736: 735: 730: 712: 707: 685: 683: 682: 677: 665: 663: 662: 657: 645: 643: 642: 637: 625: 623: 622: 617: 595: 593: 592: 587: 585: 584: 579: 578: 574: 572: 571: 562: 561: 560: 559: 558: 538: 537: 536: 535: 511: 502: 498: 490: 489: 476: 449: 448: 420: 418: 417: 412: 381:Leeds University 377:pure mathematics 367: 365: 364: 359: 337: 335: 334: 329: 306: 304: 303: 298: 275: 273: 272: 267: 259: 258: 246: 245: 229: 227: 226: 221: 213: 212: 200: 199: 183: 181: 180: 175: 167: 166: 150: 148: 147: 142: 134: 133: 121: 120: 104: 102: 101: 96: 88: 87: 75: 74: 21: 6659: 6658: 6654: 6653: 6652: 6650: 6649: 6648: 6629: 6628: 6627: 6622: 6613: 6307:First 60 primes 6302: 6266: 6166: 6149:Complex numbers 6143: 6117: 6095: 6079: 6054: 6053:Bi-twin chain ( 6044: 6018: 5998: 5982: 5966: 5942: 5918: 5902: 5877: 5863:Strobogrammatic 5801: 5775: 5669: 5633: 5625: 5619: 5618: 5601: 5592: 5577: 5554: 5542: 5530: 5521: 5506: 5497: 5484: 5476:# + 1 5474: 5469: 5461:# Â± 1 5459: 5454: 5446:! Â± 1 5442: 5430: 5422: 5414:2 âˆ’ 1 5413: 5405:2 âˆ’ 1 5404: 5396:2 + 1 5395: 5382: 5376: 5346: 5341: 5319: 5315:Strobogrammatic 5306: 5288: 5270: 5252: 5234: 5216: 5198: 5180: 5157: 5136: 5120: 5079:Divisor-related 5074: 5034: 4985: 4955: 4892: 4876: 4855: 4822: 4795: 4783: 4765: 4677: 4676:related numbers 4650: 4627: 4594: 4585:Perfect totient 4551: 4528: 4459:Highly abundant 4401: 4380: 4312: 4295: 4267: 4250: 4236:Stirling second 4142: 4119: 4080: 4062: 4019: 3968: 3905: 3866:Centered square 3834: 3817: 3779: 3764: 3731: 3716: 3668: 3667:defined numbers 3650: 3617: 3602: 3573:Double Mersenne 3559: 3540: 3462: 3448: 3446:natural numbers 3442: 3404: 3402: 3384: 3381:at Numberphile. 3368:Wayback Machine 3342: 3341: 3332: 3322: 3312:Springer-Verlag 3302: 3299: 3294: 3293: 3279: 3278: 3274: 3260: 3259: 3255: 3235: 3234: 3230: 3201: 3200: 3196: 3172: 3171: 3167: 3151: 3150: 3146: 3136: 3134: 3118: 3117: 3113: 3103: 3101: 3085: 3084: 3080: 3060: 3059: 3055: 3023: 3022: 3018: 3008: 3006: 3001: 3000: 2996: 2991: 2959: 2954: 2953: 2950: 2947: 2944: 2941: 2938: 2935: 2932: 2929: 2926: 2923: 2920: 2917: 2914: 2911: 2908: 2905: 2902: 2899: 2896: 2893: 2890: 2887: 2884: 2881: 2878: 2875: 2872: 2869: 2866: 2863: 2860: 2857: 2854: 2851: 2848: 2845: 2842: 2839: 2836: 2833: 2830: 2827: 2824: 2821: 2818: 2815: 2812: 2809: 2806: 2803: 2800: 2797: 2794: 2791: 2788: 2785: 2782: 2779: 2776: 2773: 2770: 2767: 2764: 2761: 2758: 2755: 2752: 2749: 2746: 2743: 2740: 2737: 2734: 2731: 2728: 2725: 2722: 2719: 2680: 2679: 2654: 2653: 2650: 2632: 2630:12-happy primes 2622: 2619: 2617: 2606: 2601: 2599: 2591: 2588: 2585: 2583: 2581: 2564: 2553: 2551:10-happy primes 2536: 2501: 2500: 2477: 2476: 2457: 2456: 2453: 2403: 2385: 2350: 2345: 2344: 2309: 2304: 2303: 2278: 2277: 2274: 2233: 2228: 2227: 2192: 2187: 2186: 2161: 2160: 2157: 2155:6-happy numbers 2121: 2116: 2115: 2084: 2079: 2078: 2053: 2052: 2049: 2047:4-happy numbers 2044: 2021: 2019: 2000: 1999: 1980: 1979: 1976: 1975: 1970: 1959: 1955: 1952: 1943:natural density 1939: 1907: 1906: 1887: 1886: 1865: 1860: 1859: 1838: 1833: 1832: 1813: 1812: 1793: 1792: 1773: 1772: 1742: 1729: 1713: 1694: 1666: 1628: 1627: 1599: 1586: 1573: 1557: 1538: 1510: 1472: 1471: 1443: 1430: 1417: 1404: 1388: 1369: 1341: 1336: 1335: 1302: 1289: 1276: 1248: 1210: 1209: 1181: 1168: 1140: 1102: 1101: 1073: 1060: 1032: 994: 993: 965: 952: 924: 919: 918: 893: 892: 865: 860: 859: 836: 835: 808: 803: 802: 779: 778: 777:represents the 741: 740: 688: 687: 668: 667: 648: 647: 628: 627: 602: 601: 563: 550: 521: 512: 506: 504: 481: 434: 429: 428: 403: 402: 399: 393: 344: 343: 320: 319: 289: 288: 250: 237: 232: 231: 204: 191: 186: 185: 158: 153: 152: 125: 112: 107: 106: 79: 66: 61: 60: 39: 28: 23: 22: 15: 12: 11: 5: 6657: 6655: 6647: 6646: 6641: 6631: 6630: 6624: 6623: 6618: 6615: 6614: 6612: 6611: 6606: 6601: 6596: 6591: 6586: 6581: 6576: 6571: 6566: 6561: 6556: 6551: 6546: 6541: 6536: 6531: 6526: 6521: 6516: 6511: 6506: 6501: 6496: 6491: 6486: 6481: 6476: 6471: 6466: 6461: 6456: 6451: 6446: 6441: 6436: 6431: 6426: 6421: 6416: 6411: 6406: 6401: 6396: 6391: 6386: 6381: 6376: 6371: 6366: 6361: 6356: 6351: 6346: 6341: 6336: 6331: 6326: 6321: 6316: 6310: 6308: 6304: 6303: 6301: 6300: 6295: 6290: 6285: 6280: 6278:Probable prime 6274: 6272: 6271:Related topics 6268: 6267: 6265: 6264: 6259: 6254: 6252:Sphenic number 6249: 6244: 6239: 6234: 6233: 6232: 6227: 6222: 6217: 6212: 6207: 6202: 6197: 6192: 6187: 6176: 6174: 6168: 6167: 6165: 6164: 6162:Gaussian prime 6159: 6153: 6151: 6145: 6144: 6142: 6141: 6140: 6130: 6125: 6123: 6119: 6118: 6116: 6115: 6091: 6087: + 1 6075: 6070: 6049: 6046: 6045: 6043: 6042: 6014: 5994: 5990: + 6 5978: 5974: + 4 5962: 5958: + 8 5938: 5934: + 6 5914: 5910: + 2 5897: 5895: 5883: 5879: 5878: 5876: 5875: 5870: 5865: 5860: 5855: 5850: 5845: 5840: 5835: 5830: 5825: 5820: 5815: 5810: 5805: 5797: 5792: 5786: 5784: 5777: 5776: 5774: 5773: 5768: 5763: 5758: 5753: 5748: 5743: 5738: 5733: 5728: 5723: 5718: 5713: 5708: 5703: 5698: 5693: 5688: 5677: 5675: 5671: 5670: 5668: 5667: 5662: 5657: 5652: 5647: 5641: 5639: 5635: 5634: 5632: 5631: 5614: 5610: âˆ’ 1 5597: 5588: 5573: 5550: 5538: 5526: 5517: 5502: 5493: 5489: + 1 5480: 5472: 5465: 5457: 5450: 5438: 5426: 5418: 5409: 5400: 5390: 5388: 5384: 5383: 5377: 5375: 5374: 5367: 5360: 5352: 5343: 5342: 5340: 5339: 5328: 5325: 5324: 5321: 5320: 5318: 5317: 5311: 5308: 5307: 5301: 5294: 5293: 5290: 5289: 5287: 5286: 5281: 5275: 5272: 5271: 5265: 5258: 5257: 5254: 5253: 5251: 5250: 5248:Sorting number 5245: 5243:Pancake number 5239: 5236: 5235: 5229: 5222: 5221: 5218: 5217: 5215: 5214: 5209: 5203: 5200: 5199: 5193: 5186: 5185: 5182: 5181: 5179: 5178: 5173: 5168: 5162: 5159: 5158: 5155:Binary numbers 5153: 5146: 5145: 5142: 5141: 5138: 5137: 5135: 5134: 5128: 5126: 5122: 5121: 5119: 5118: 5113: 5108: 5103: 5098: 5093: 5088: 5082: 5080: 5076: 5075: 5073: 5072: 5067: 5062: 5057: 5052: 5046: 5044: 5036: 5035: 5033: 5032: 5027: 5022: 5017: 5012: 5007: 5002: 4996: 4994: 4987: 4986: 4984: 4983: 4982: 4981: 4970: 4968: 4965:P-adic numbers 4961: 4960: 4957: 4956: 4954: 4953: 4952: 4951: 4941: 4936: 4931: 4926: 4921: 4916: 4911: 4906: 4900: 4898: 4894: 4893: 4891: 4890: 4884: 4882: 4881:Coding-related 4878: 4877: 4875: 4874: 4869: 4863: 4861: 4857: 4856: 4854: 4853: 4848: 4843: 4838: 4832: 4830: 4821: 4820: 4819: 4818: 4816:Multiplicative 4813: 4802: 4800: 4785: 4784: 4780:Numeral system 4778: 4771: 4770: 4767: 4766: 4764: 4763: 4758: 4753: 4748: 4743: 4738: 4733: 4728: 4723: 4718: 4713: 4708: 4703: 4698: 4693: 4688: 4682: 4679: 4678: 4667: 4660: 4659: 4656: 4655: 4652: 4651: 4649: 4648: 4643: 4637: 4635: 4629: 4628: 4626: 4625: 4620: 4615: 4610: 4604: 4602: 4596: 4595: 4593: 4592: 4587: 4582: 4577: 4572: 4570:Highly totient 4567: 4561: 4559: 4553: 4552: 4550: 4549: 4544: 4538: 4536: 4530: 4529: 4527: 4526: 4521: 4516: 4511: 4506: 4501: 4496: 4491: 4486: 4481: 4476: 4471: 4466: 4461: 4456: 4451: 4446: 4441: 4436: 4431: 4426: 4424:Almost perfect 4421: 4415: 4413: 4403: 4402: 4393: 4386: 4385: 4382: 4381: 4379: 4378: 4373: 4368: 4363: 4358: 4353: 4348: 4343: 4338: 4333: 4328: 4323: 4317: 4314: 4313: 4308: 4301: 4300: 4297: 4296: 4294: 4293: 4288: 4283: 4278: 4272: 4269: 4268: 4263: 4256: 4255: 4252: 4251: 4249: 4248: 4243: 4238: 4233: 4231:Stirling first 4228: 4223: 4218: 4213: 4208: 4203: 4198: 4193: 4188: 4183: 4178: 4173: 4168: 4163: 4158: 4153: 4147: 4144: 4143: 4140: 4133: 4132: 4129: 4128: 4125: 4124: 4121: 4120: 4118: 4117: 4112: 4107: 4101: 4099: 4092: 4086: 4085: 4082: 4081: 4079: 4078: 4072: 4070: 4064: 4063: 4061: 4060: 4055: 4050: 4045: 4040: 4035: 4029: 4027: 4021: 4020: 4018: 4017: 4012: 4007: 4002: 3997: 3991: 3989: 3980: 3974: 3973: 3970: 3969: 3967: 3966: 3961: 3956: 3951: 3946: 3941: 3936: 3931: 3926: 3921: 3915: 3913: 3907: 3906: 3904: 3903: 3898: 3893: 3888: 3883: 3878: 3873: 3868: 3863: 3857: 3855: 3846: 3836: 3835: 3830: 3823: 3822: 3819: 3818: 3816: 3815: 3810: 3805: 3800: 3795: 3790: 3784: 3781: 3780: 3777: 3770: 3769: 3766: 3765: 3763: 3762: 3757: 3752: 3747: 3742: 3736: 3733: 3732: 3729: 3722: 3721: 3718: 3717: 3715: 3714: 3709: 3704: 3699: 3694: 3689: 3684: 3679: 3673: 3670: 3669: 3663: 3656: 3655: 3652: 3651: 3649: 3648: 3643: 3638: 3633: 3628: 3622: 3619: 3618: 3615: 3608: 3607: 3604: 3603: 3601: 3600: 3595: 3590: 3585: 3580: 3575: 3570: 3564: 3561: 3560: 3553: 3546: 3545: 3542: 3541: 3539: 3538: 3533: 3528: 3523: 3518: 3513: 3508: 3503: 3498: 3493: 3488: 3483: 3478: 3473: 3467: 3464: 3463: 3457: 3450: 3449: 3443: 3441: 3440: 3433: 3426: 3418: 3412: 3411: 3385:Symonds, Ria. 3382: 3376: 3370: 3358: 3347:"Happy Number" 3339: 3331: 3330:External links 3328: 3327: 3326: 3320: 3298: 3295: 3292: 3291: 3272: 3253: 3228: 3194: 3165: 3144: 3111: 3078: 3053: 3016: 2993: 2992: 2990: 2987: 2986: 2985: 2980: 2975: 2973:Harshad number 2970: 2965: 2958: 2955: 2718: 2693: 2690: 2687: 2667: 2664: 2661: 2649: 2646: 2645: 2644: 2631: 2628: 2614:Mersenne prime 2575: 2574: 2552: 2549: 2548: 2547: 2535: 2534:6-happy primes 2532: 2508: 2484: 2464: 2452: 2449: 2448: 2447: 2431: 2430: 2414: 2413: 2396: 2395: 2363: 2360: 2357: 2353: 2341: 2340: 2322: 2319: 2316: 2312: 2291: 2288: 2285: 2273: 2270: 2269: 2268: 2246: 2243: 2240: 2236: 2224: 2223: 2205: 2202: 2199: 2195: 2174: 2171: 2168: 2156: 2153: 2134: 2131: 2128: 2124: 2097: 2094: 2091: 2087: 2066: 2063: 2060: 2048: 2045: 2043: 2042:-happy numbers 2036: 2007: 1987: 1971: 1960: 1954: 1951: 1948: 1938: 1937:-happy numbers 1931: 1914: 1894: 1872: 1868: 1845: 1841: 1820: 1800: 1780: 1769: 1768: 1757: 1754: 1749: 1745: 1741: 1736: 1732: 1728: 1725: 1720: 1716: 1712: 1707: 1704: 1701: 1697: 1693: 1690: 1687: 1684: 1679: 1676: 1673: 1669: 1665: 1662: 1659: 1656: 1651: 1646: 1643: 1640: 1636: 1625: 1614: 1611: 1606: 1602: 1598: 1593: 1589: 1585: 1580: 1576: 1572: 1569: 1564: 1560: 1556: 1551: 1548: 1545: 1541: 1537: 1534: 1531: 1528: 1523: 1520: 1517: 1513: 1509: 1506: 1503: 1500: 1495: 1490: 1487: 1484: 1480: 1469: 1458: 1455: 1450: 1446: 1442: 1437: 1433: 1429: 1424: 1420: 1416: 1411: 1407: 1403: 1400: 1395: 1391: 1387: 1382: 1379: 1376: 1372: 1368: 1365: 1362: 1359: 1354: 1351: 1348: 1344: 1329: 1328: 1317: 1314: 1309: 1305: 1301: 1296: 1292: 1288: 1283: 1279: 1275: 1272: 1269: 1266: 1261: 1258: 1255: 1251: 1247: 1244: 1241: 1238: 1233: 1228: 1225: 1222: 1218: 1207: 1196: 1193: 1188: 1184: 1180: 1175: 1171: 1167: 1164: 1161: 1158: 1153: 1150: 1147: 1143: 1139: 1136: 1133: 1130: 1125: 1120: 1117: 1114: 1110: 1099: 1088: 1085: 1080: 1076: 1072: 1067: 1063: 1059: 1056: 1053: 1050: 1045: 1042: 1039: 1035: 1031: 1028: 1025: 1022: 1017: 1012: 1009: 1006: 1002: 991: 980: 977: 972: 968: 964: 959: 955: 951: 948: 945: 942: 937: 934: 931: 927: 900: 878: 875: 872: 868: 843: 821: 818: 815: 811: 786: 764: 759: 756: 753: 749: 728: 725: 722: 719: 716: 711: 706: 703: 700: 696: 675: 655: 635: 615: 612: 609: 598: 597: 583: 577: 570: 566: 557: 553: 548: 544: 541: 534: 531: 528: 524: 519: 515: 509: 501: 497: 493: 488: 484: 480: 475: 472: 469: 465: 461: 458: 455: 452: 447: 444: 441: 437: 410: 401:Formally, let 392: 389: 357: 354: 351: 327: 313:natural number 296: 265: 262: 257: 253: 249: 244: 240: 219: 216: 211: 207: 203: 198: 194: 173: 170: 165: 161: 140: 137: 132: 128: 124: 119: 115: 94: 91: 86: 82: 78: 73: 69: 32:Harshad number 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 6656: 6645: 6642: 6640: 6637: 6636: 6634: 6621: 6616: 6610: 6607: 6605: 6602: 6600: 6597: 6595: 6592: 6590: 6587: 6585: 6582: 6580: 6577: 6575: 6572: 6570: 6567: 6565: 6562: 6560: 6557: 6555: 6552: 6550: 6547: 6545: 6542: 6540: 6537: 6535: 6532: 6530: 6527: 6525: 6522: 6520: 6517: 6515: 6512: 6510: 6507: 6505: 6502: 6500: 6497: 6495: 6492: 6490: 6487: 6485: 6482: 6480: 6477: 6475: 6472: 6470: 6467: 6465: 6462: 6460: 6457: 6455: 6452: 6450: 6447: 6445: 6442: 6440: 6437: 6435: 6432: 6430: 6427: 6425: 6422: 6420: 6417: 6415: 6412: 6410: 6407: 6405: 6402: 6400: 6397: 6395: 6392: 6390: 6387: 6385: 6382: 6380: 6377: 6375: 6372: 6370: 6367: 6365: 6362: 6360: 6357: 6355: 6352: 6350: 6347: 6345: 6342: 6340: 6337: 6335: 6332: 6330: 6327: 6325: 6322: 6320: 6317: 6315: 6312: 6311: 6309: 6305: 6299: 6296: 6294: 6291: 6289: 6288:Illegal prime 6286: 6284: 6281: 6279: 6276: 6275: 6273: 6269: 6263: 6260: 6258: 6255: 6253: 6250: 6248: 6245: 6243: 6240: 6238: 6235: 6231: 6228: 6226: 6223: 6221: 6218: 6216: 6213: 6211: 6208: 6206: 6203: 6201: 6198: 6196: 6193: 6191: 6188: 6186: 6183: 6182: 6181: 6178: 6177: 6175: 6173: 6169: 6163: 6160: 6158: 6155: 6154: 6152: 6150: 6146: 6139: 6136: 6135: 6134: 6133:Largest known 6131: 6129: 6126: 6124: 6120: 6114: 6110: 6106: 6102: 6098: 6092: 6090: 6086: 6082: 6076: 6074: 6071: 6069: 6065: 6061: 6057: 6051: 6050: 6041: 6038: 6035: +  6034: 6030: 6026: 6023: âˆ’  6022: 6015: 6013: 6009: 6005: 6002: +  6001: 5995: 5993: 5989: 5985: 5979: 5977: 5973: 5969: 5963: 5961: 5957: 5953: 5949: 5945: 5939: 5937: 5933: 5929: 5925: 5921: 5915: 5913: 5909: 5905: 5899: 5898: 5896: 5894: 5892: 5887: 5884: 5880: 5874: 5871: 5869: 5866: 5864: 5861: 5859: 5856: 5854: 5851: 5849: 5846: 5844: 5841: 5839: 5836: 5834: 5831: 5829: 5826: 5824: 5821: 5819: 5816: 5814: 5811: 5809: 5806: 5804: 5798: 5796: 5793: 5791: 5788: 5787: 5785: 5782: 5778: 5772: 5769: 5767: 5764: 5762: 5759: 5757: 5754: 5752: 5749: 5747: 5744: 5742: 5739: 5737: 5734: 5732: 5729: 5727: 5724: 5722: 5719: 5717: 5714: 5712: 5709: 5707: 5704: 5702: 5699: 5697: 5694: 5692: 5689: 5686: 5682: 5679: 5678: 5676: 5672: 5666: 5663: 5661: 5658: 5656: 5653: 5651: 5648: 5646: 5643: 5642: 5640: 5636: 5630: 5624: 5615: 5613: 5609: 5605: 5598: 5596: 5589: 5587: 5584: 5581: +  5580: 5574: 5572: 5569: 5566: âˆ’  5565: 5561: 5558: âˆ’  5557: 5551: 5549: 5545: 5539: 5537: 5533: 5527: 5525: 5518: 5516: 5513: 5510: +  5509: 5503: 5501: 5494: 5492: 5488: 5483:Pythagorean ( 5481: 5479: 5475: 5466: 5464: 5460: 5451: 5449: 5445: 5439: 5437: 5433: 5427: 5425: 5419: 5417: 5410: 5408: 5401: 5399: 5392: 5391: 5389: 5385: 5380: 5373: 5368: 5366: 5361: 5359: 5354: 5353: 5350: 5338: 5334: 5330: 5329: 5326: 5316: 5313: 5312: 5309: 5304: 5299: 5295: 5285: 5282: 5280: 5277: 5276: 5273: 5268: 5263: 5259: 5249: 5246: 5244: 5241: 5240: 5237: 5232: 5227: 5223: 5213: 5210: 5208: 5205: 5204: 5201: 5197: 5191: 5187: 5177: 5174: 5172: 5169: 5167: 5164: 5163: 5160: 5156: 5151: 5147: 5133: 5130: 5129: 5127: 5123: 5117: 5114: 5112: 5109: 5107: 5106:Polydivisible 5104: 5102: 5099: 5097: 5094: 5092: 5089: 5087: 5084: 5083: 5081: 5077: 5071: 5068: 5066: 5063: 5061: 5058: 5056: 5053: 5051: 5048: 5047: 5045: 5042: 5037: 5031: 5028: 5026: 5023: 5021: 5018: 5016: 5013: 5011: 5008: 5006: 5003: 5001: 4998: 4997: 4995: 4992: 4988: 4980: 4977: 4976: 4975: 4972: 4971: 4969: 4966: 4962: 4950: 4947: 4946: 4945: 4942: 4940: 4937: 4935: 4932: 4930: 4927: 4925: 4922: 4920: 4917: 4915: 4912: 4910: 4907: 4905: 4902: 4901: 4899: 4895: 4889: 4886: 4885: 4883: 4879: 4873: 4870: 4868: 4865: 4864: 4862: 4860:Digit product 4858: 4852: 4849: 4847: 4844: 4842: 4839: 4837: 4834: 4833: 4831: 4829: 4825: 4817: 4814: 4812: 4809: 4808: 4807: 4804: 4803: 4801: 4799: 4794: 4790: 4786: 4781: 4776: 4772: 4762: 4759: 4757: 4754: 4752: 4749: 4747: 4744: 4742: 4739: 4737: 4734: 4732: 4729: 4727: 4724: 4722: 4719: 4717: 4714: 4712: 4709: 4707: 4704: 4702: 4699: 4697: 4696:ErdƑs–Nicolas 4694: 4692: 4689: 4687: 4684: 4683: 4680: 4675: 4671: 4665: 4661: 4647: 4644: 4642: 4639: 4638: 4636: 4634: 4630: 4624: 4621: 4619: 4616: 4614: 4611: 4609: 4606: 4605: 4603: 4601: 4597: 4591: 4588: 4586: 4583: 4581: 4578: 4576: 4573: 4571: 4568: 4566: 4563: 4562: 4560: 4558: 4554: 4548: 4545: 4543: 4540: 4539: 4537: 4535: 4531: 4525: 4522: 4520: 4517: 4515: 4514:Superabundant 4512: 4510: 4507: 4505: 4502: 4500: 4497: 4495: 4492: 4490: 4487: 4485: 4482: 4480: 4477: 4475: 4472: 4470: 4467: 4465: 4462: 4460: 4457: 4455: 4452: 4450: 4447: 4445: 4442: 4440: 4437: 4435: 4432: 4430: 4427: 4425: 4422: 4420: 4417: 4416: 4414: 4412: 4408: 4404: 4400: 4396: 4391: 4387: 4377: 4374: 4372: 4369: 4367: 4364: 4362: 4359: 4357: 4354: 4352: 4349: 4347: 4344: 4342: 4339: 4337: 4334: 4332: 4329: 4327: 4324: 4322: 4319: 4318: 4315: 4311: 4306: 4302: 4292: 4289: 4287: 4284: 4282: 4279: 4277: 4274: 4273: 4270: 4266: 4261: 4257: 4247: 4244: 4242: 4239: 4237: 4234: 4232: 4229: 4227: 4224: 4222: 4219: 4217: 4214: 4212: 4209: 4207: 4204: 4202: 4199: 4197: 4194: 4192: 4189: 4187: 4184: 4182: 4179: 4177: 4174: 4172: 4169: 4167: 4164: 4162: 4159: 4157: 4154: 4152: 4149: 4148: 4145: 4138: 4134: 4116: 4113: 4111: 4108: 4106: 4103: 4102: 4100: 4096: 4093: 4091: 4090:4-dimensional 4087: 4077: 4074: 4073: 4071: 4069: 4065: 4059: 4056: 4054: 4051: 4049: 4046: 4044: 4041: 4039: 4036: 4034: 4031: 4030: 4028: 4026: 4022: 4016: 4013: 4011: 4008: 4006: 4003: 4001: 4000:Centered cube 3998: 3996: 3993: 3992: 3990: 3988: 3984: 3981: 3979: 3978:3-dimensional 3975: 3965: 3962: 3960: 3957: 3955: 3952: 3950: 3947: 3945: 3942: 3940: 3937: 3935: 3932: 3930: 3927: 3925: 3922: 3920: 3917: 3916: 3914: 3912: 3908: 3902: 3899: 3897: 3894: 3892: 3889: 3887: 3884: 3882: 3879: 3877: 3874: 3872: 3869: 3867: 3864: 3862: 3859: 3858: 3856: 3854: 3850: 3847: 3845: 3844:2-dimensional 3841: 3837: 3833: 3828: 3824: 3814: 3811: 3809: 3806: 3804: 3801: 3799: 3796: 3794: 3791: 3789: 3788:Nonhypotenuse 3786: 3785: 3782: 3775: 3771: 3761: 3758: 3756: 3753: 3751: 3748: 3746: 3743: 3741: 3738: 3737: 3734: 3727: 3723: 3713: 3710: 3708: 3705: 3703: 3700: 3698: 3695: 3693: 3690: 3688: 3685: 3683: 3680: 3678: 3675: 3674: 3671: 3666: 3661: 3657: 3647: 3644: 3642: 3639: 3637: 3634: 3632: 3629: 3627: 3624: 3623: 3620: 3613: 3609: 3599: 3596: 3594: 3591: 3589: 3586: 3584: 3581: 3579: 3576: 3574: 3571: 3569: 3566: 3565: 3562: 3557: 3551: 3547: 3537: 3534: 3532: 3529: 3527: 3526:Perfect power 3524: 3522: 3519: 3517: 3516:Seventh power 3514: 3512: 3509: 3507: 3504: 3502: 3499: 3497: 3494: 3492: 3489: 3487: 3484: 3482: 3479: 3477: 3474: 3472: 3469: 3468: 3465: 3460: 3455: 3451: 3447: 3439: 3434: 3432: 3427: 3425: 3420: 3419: 3416: 3400: 3396: 3392: 3388: 3383: 3380: 3377: 3374: 3373:Happy Numbers 3371: 3369: 3365: 3362: 3359: 3354: 3353: 3348: 3345: 3340: 3338: 3334: 3333: 3329: 3323: 3321:0-387-20860-7 3317: 3313: 3309: 3305: 3301: 3300: 3296: 3287: 3283: 3276: 3273: 3268: 3264: 3257: 3254: 3249: 3248: 3242: 3238: 3232: 3229: 3225: 3219: 3215: 3211: 3210: 3205: 3198: 3195: 3190: 3189: 3183: 3181: 3175: 3169: 3166: 3160: 3155: 3148: 3145: 3132: 3131: 3125: 3121: 3115: 3112: 3099: 3098: 3092: 3088: 3082: 3079: 3074: 3073: 3067: 3063: 3057: 3054: 3049: 3045: 3040: 3035: 3031: 3027: 3020: 3017: 3004: 2998: 2995: 2988: 2984: 2981: 2979: 2976: 2974: 2971: 2969: 2966: 2964: 2961: 2960: 2956: 2716: 2714: 2709: 2707: 2691: 2688: 2685: 2665: 2662: 2659: 2647: 2641: 2640: 2639: 2637: 2629: 2627: 2615: 2610: 2580: 2572: 2567: 2562: 2561: 2560: 2558: 2550: 2545: 2544: 2543: 2541: 2533: 2531: 2529: 2525: 2520: 2506: 2498: 2482: 2462: 2450: 2444: 2443: 2442: 2440: 2435: 2428: 2427: 2426: 2424: 2420: 2411: 2406: 2401: 2400: 2399: 2393: 2388: 2382: 2381: 2380: 2377: 2361: 2358: 2355: 2351: 2338: 2337: 2336: 2320: 2317: 2314: 2310: 2289: 2286: 2283: 2271: 2265: 2264: 2263: 2260: 2244: 2241: 2238: 2234: 2221: 2220: 2219: 2203: 2200: 2197: 2193: 2172: 2169: 2166: 2154: 2152: 2150: 2132: 2129: 2126: 2122: 2113: 2095: 2092: 2089: 2085: 2064: 2061: 2058: 2046: 2041: 2037: 2035: 2033: 2029: 2005: 1985: 1974: 1968: 1964: 1949: 1947: 1944: 1936: 1932: 1930: 1928: 1912: 1892: 1870: 1866: 1843: 1839: 1818: 1798: 1778: 1755: 1752: 1747: 1743: 1739: 1734: 1730: 1726: 1718: 1714: 1705: 1702: 1699: 1695: 1691: 1685: 1677: 1674: 1671: 1667: 1663: 1657: 1649: 1644: 1641: 1638: 1634: 1626: 1612: 1609: 1604: 1600: 1596: 1591: 1587: 1583: 1578: 1574: 1570: 1562: 1558: 1549: 1546: 1543: 1539: 1535: 1529: 1521: 1518: 1515: 1511: 1507: 1501: 1493: 1488: 1485: 1482: 1478: 1470: 1456: 1453: 1448: 1444: 1440: 1435: 1431: 1427: 1422: 1418: 1414: 1409: 1405: 1401: 1393: 1389: 1380: 1377: 1374: 1370: 1366: 1360: 1352: 1349: 1346: 1342: 1334: 1333: 1332: 1315: 1312: 1307: 1303: 1299: 1294: 1290: 1286: 1281: 1277: 1273: 1267: 1259: 1256: 1253: 1249: 1245: 1239: 1231: 1226: 1223: 1220: 1216: 1208: 1194: 1191: 1186: 1182: 1178: 1173: 1169: 1165: 1159: 1151: 1148: 1145: 1141: 1137: 1131: 1123: 1118: 1115: 1112: 1108: 1100: 1086: 1083: 1078: 1074: 1070: 1065: 1061: 1057: 1051: 1043: 1040: 1037: 1033: 1029: 1023: 1015: 1010: 1007: 1004: 1000: 992: 978: 975: 970: 966: 962: 957: 953: 949: 943: 935: 932: 929: 925: 917: 916: 915: 912: 898: 891:, then it is 876: 873: 870: 866: 857: 841: 819: 816: 813: 809: 800: 784: 762: 757: 754: 751: 747: 726: 723: 717: 709: 704: 701: 698: 694: 673: 653: 633: 613: 610: 607: 581: 575: 568: 564: 555: 551: 542: 539: 532: 529: 526: 522: 513: 507: 495: 491: 486: 482: 473: 470: 467: 463: 459: 453: 445: 442: 439: 435: 427: 426: 425: 424: 408: 398: 390: 388: 386: 382: 378: 374: 369: 355: 352: 349: 341: 325: 318: 314: 310: 294: 285: 283: 279: 263: 260: 255: 251: 247: 242: 238: 217: 214: 209: 205: 201: 196: 192: 171: 168: 163: 159: 138: 135: 130: 126: 122: 117: 113: 92: 89: 84: 80: 76: 71: 67: 58: 54: 53:number theory 45: 41: 37: 33: 19: 6242:Almost prime 6200:Euler–Jacobi 6108: 6104: 6100: 6096: 6094:Cunningham ( 6084: 6080: 6063: 6059: 6055: 6036: 6032: 6028: 6024: 6020: 6019:consecutive 6007: 6003: 5999: 5987: 5983: 5971: 5967: 5955: 5951: 5947: 5943: 5941:Quadruplet ( 5931: 5927: 5923: 5919: 5907: 5903: 5890: 5838:Full reptend 5696:Wolstenholme 5691:Wall–Sun–Sun 5622: 5607: 5603: 5582: 5578: 5567: 5563: 5559: 5555: 5543: 5531: 5511: 5507: 5486: 5470: 5455: 5443: 5431: 5379:Prime number 5070:Transposable 4948: 4934:Narcissistic 4841:Digital root 4761:Super-Poulet 4721:Jordan–PĂłlya 4670:prime factor 4575:Noncototient 4542:Almost prime 4524:Superperfect 4499:Refactorable 4494:Quasiperfect 4469:Hyperperfect 4310:Pseudoprimes 4281:Wall–Sun–Sun 4216:Ordered Bell 4186:Fuss–Catalan 4098:non-centered 4048:Dodecahedral 4025:non-centered 3911:non-centered 3813:Wolstenholme 3558:× 2 ± 1 3555: 3554:Of the form 3521:Eighth power 3501:Fourth power 3403:. Retrieved 3399:the original 3390: 3350: 3307: 3304:Guy, Richard 3285: 3275: 3266: 3256: 3244: 3231: 3213: 3207: 3197: 3185: 3179: 3168: 3159:math/0607213 3147: 3135:. Retrieved 3127: 3114: 3102:. Retrieved 3094: 3081: 3069: 3056: 3029: 3025: 3019: 3009:16 September 3007:. Retrieved 3003:"Sad Number" 2997: 2978:Lucky number 2930:pdi_function 2906:seen_numbers 2900:seen_numbers 2864:seen_numbers 2723:pdi_function 2710: 2651: 2633: 2611: 2576: 2554: 2537: 2521: 2454: 2451:Happy primes 2438: 2436: 2432: 2422: 2418: 2415: 2397: 2378: 2342: 2275: 2261: 2225: 2158: 2050: 2039: 1977: 1940: 1934: 1926: 1770: 1330: 913: 599: 400: 370: 309:happy number 308: 286: 281: 277: 57:happy number 56: 50: 40: 35: 6225:Somer–Lucas 6180:Pseudoprime 5818:Truncatable 5790:Palindromic 5674:By property 5453:Primorial ( 5441:Factorial ( 5091:Extravagant 5086:Equidigital 5041:permutation 5000:Palindromic 4974:Automorphic 4872:Sum-product 4851:Sum-product 4806:Persistence 4701:ErdƑs–Woods 4623:Untouchable 4504:Semiperfect 4454:Hemiperfect 4115:Tesseractic 4053:Icosahedral 4033:Tetrahedral 3964:Dodecagonal 3665:Recursively 3536:Prime power 3511:Sixth power 3506:Fifth power 3486:Power of 10 3444:Classes of 3395:Brady Haran 3391:Numberphile 2495:-happy and 1950:Happy bases 626:, a number 373:Reg Allenby 317:number base 315:in a given 18:Happy prime 6633:Categories 6262:Pernicious 6257:Interprime 6017:Balanced ( 5808:Permutable 5783:-dependent 5600:Williams ( 5496:Pierpont ( 5421:Wagstaff 5403:Mersenne ( 5387:By formula 5303:Graphemics 5176:Pernicious 5030:Undulating 5005:Pandigital 4979:Trimorphic 4580:Nontotient 4429:Arithmetic 4043:Octahedral 3944:Heptagonal 3934:Pentagonal 3919:Triangular 3760:SierpiƄski 3682:Jacobsthal 3481:Power of 3 3476:Power of 2 3297:Literature 2989:References 911:-unhappy. 686:such that 395:See also: 6298:Prime gap 6247:Semiprime 6210:Frobenius 5917:Triplet ( 5716:Ramanujan 5711:Fortunate 5681:Wieferich 5645:Fibonacci 5576:Leyland ( 5541:Woodall ( 5520:Solinas ( 5505:Quartan ( 5060:Parasitic 4909:Factorion 4836:Digit sum 4828:Digit sum 4646:Fortunate 4633:Primorial 4547:Semiprime 4484:Practical 4449:Descartes 4444:Deficient 4434:Betrothed 4276:Wieferich 4105:Pentatope 4068:pyramidal 3959:Decagonal 3954:Nonagonal 3949:Octagonal 3939:Hexagonal 3798:Practical 3745:Congruent 3677:Fibonacci 3641:Loeschian 3352:MathWorld 3222:Cited in 3039:1110.3836 2038:Specific 1927:happiness 799:iteration 600:for base 540:− 500:⌋ 492:⁡ 479:⌊ 464:∑ 6190:Elliptic 5965:Cousin ( 5882:Patterns 5873:Tetradic 5868:Dihedral 5833:Primeval 5828:Delicate 5813:Circular 5800:Repunit 5591:Thabit ( 5529:Cullen ( 5468:Euclid ( 5394:Fermat ( 5132:Friedman 5065:Primeval 5010:Repdigit 4967:-related 4914:Kaprekar 4888:Meertens 4811:Additive 4798:dynamics 4706:Friendly 4618:Sociable 4608:Amicable 4419:Abundant 4399:dynamics 4221:Schröder 4211:Narayana 4181:Eulerian 4171:Delannoy 4166:Dedekind 3987:centered 3853:centered 3740:Amenable 3697:Narayana 3687:Leonardo 3583:Mersenne 3531:Powerful 3471:Achilles 3364:Archived 3306:(2004). 3032:(2): 2. 3026:Integers 2957:See also 2834:is_happy 2626:digits. 1885:in base 739:, where 387::§E34). 385:Guy 2004 6185:Catalan 6122:By size 5893:-tuples 5823:Minimal 5726:Regular 5617:Mills ( 5553:Cuban ( 5429:Proth ( 5381:classes 5305:related 5269:related 5233:related 5231:Sorting 5116:Vampire 5101:Harshad 5043:related 5015:Repunit 4929:Lychrel 4904:Dudeney 4756:StĂžrmer 4751:Sphenic 4736:Regular 4674:divisor 4613:Perfect 4509:Sublime 4479:Perfect 4206:Motzkin 4161:Catalan 3702:Padovan 3636:Leyland 3631:Idoneal 3626:Hilbert 3598:Woodall 3405:2 April 3286:utm.edu 3267:utm.edu 3239:(ed.). 3176:(ed.). 3137:8 April 3122:(ed.). 3104:8 April 3089:(ed.). 3064:(ed.). 3044:Bibcode 2636:base 12 2569:in the 2566:A035497 2557:base 10 2408:in the 2405:A124095 2390:in the 2387:A007770 282:unhappy 6230:Strong 6220:Perrin 6205:Fermat 5981:Sexy ( 5901:Twin ( 5843:Unique 5771:Unique 5731:Strong 5721:Pillai 5701:Wilson 5665:Perrin 5171:Odious 5096:Frugal 5050:Cyclic 5039:Digit- 4746:Smooth 4731:Pronic 4691:Cyclic 4668:Other 4641:Euclid 4291:Wilson 4265:Primes 3924:Square 3793:Polite 3755:Riesel 3750:Knödel 3712:Perrin 3593:Thabit 3578:Fermat 3568:Cullen 3491:Square 3459:Powers 3318:  2945:number 2942:return 2936:number 2924:number 2918:number 2891:number 2879:number 2840:number 2825:return 2816:number 2810:number 2792:number 2768:number 2729:number 2713:Python 2540:base 6 2528:base 4 2524:base 2 2149:base 4 2032:base 4 2028:base 2 1967:base 4 1963:base 2 834:, and 105:, and 6215:Lucas 6195:Euler 5848:Happy 5795:Emirp 5761:Higgs 5756:Super 5736:Stern 5706:Lucky 5650:Lucas 5212:Prime 5207:Lucky 5196:sieve 5125:Other 5111:Smith 4991:Digit 4949:Happy 4924:Keith 4897:Other 4741:Rough 4711:Giuga 4176:Euler 4038:Cubic 3692:Lucas 3588:Proth 3154:arXiv 3034:arXiv 2876:while 2852:-> 2828:total 2780:total 2765:while 2756:total 2582:10 + 2497:prime 1905:) is 311:is a 36:harƛa 6138:list 6073:Chen 5853:Self 5781:Base 5751:Good 5685:pair 5655:Pell 5606:−1)· 5166:Evil 4846:Self 4796:and 4686:Blum 4397:and 4201:Lobb 4156:Cake 4151:Bell 3901:Star 3808:Ulam 3707:Pell 3496:Cube 3407:2013 3316:ISBN 3245:The 3186:The 3139:2011 3128:The 3106:2011 3095:The 3070:The 3011:2009 2882:> 2855:bool 2822:base 2798:base 2771:> 2735:base 2577:The 2571:OEIS 2526:and 2410:OEIS 2392:OEIS 2276:For 2159:For 2114:for 2051:For 2030:and 2026:are 1965:and 1961:Are 1390:1335 797:-th 611:> 342:for 184:and 55:, a 6609:281 6604:277 6599:271 6594:269 6589:263 6584:257 6579:251 6574:241 6569:239 6564:233 6559:229 6554:227 6549:223 6544:211 6539:199 6534:197 6529:193 6524:191 6519:181 6514:179 6509:173 6504:167 6499:163 6494:157 6489:151 6484:149 6479:139 6474:137 6469:131 6464:127 6459:113 6454:109 6449:107 6444:103 6439:101 6099:, 2 6083:, 2 6004:a·n 5562:)/( 5284:Ban 4672:or 4191:Lah 2912:add 2894:not 2888:and 2870:set 2846:int 2831:def 2786:pow 2741:int 2720:def 2634:In 2623:064 2620:837 2602:007 2600:150 2596:+ 1 2589:247 2586:426 2555:In 2538:In 1658:347 1559:112 1502:347 1361:347 1268:100 1195:100 858:of 801:of 646:is 547:mod 518:mod 483:log 379:at 280:or 278:sad 51:In 6635:: 6434:97 6429:89 6424:83 6419:79 6414:73 6409:71 6404:67 6399:61 6394:59 6389:53 6384:47 6379:43 6374:41 6369:37 6364:31 6359:29 6354:23 6349:19 6344:17 6339:13 6334:11 6031:, 6027:, 6006:, 5986:, 5970:, 5946:, 5922:, 5906:, 3393:. 3389:. 3349:. 3314:. 3284:. 3265:. 3243:. 3214:13 3212:. 3206:. 3184:. 3126:. 3093:. 3068:. 3042:. 3030:13 3028:. 2948:== 2897:in 2873:() 2819:// 2783:+= 2750:): 2747:10 2708:. 2692:10 2618:12 2594:10 2573:). 2455:A 2412:). 2394:). 2290:10 2034:. 2024:10 1867:10 1831:, 1715:10 1530:44 1457:44 1260:10 1240:19 1227:10 1160:68 1152:10 1132:19 1119:10 1087:68 1052:82 1044:10 1024:19 1011:10 979:82 944:19 936:10 368:. 284:. 218:37 172:16 93:10 6329:7 6324:5 6319:3 6314:2 6113:) 6109:p 6105:p 6101:p 6097:p 6089:) 6085:p 6081:p 6068:) 6064:n 6060:n 6056:n 6040:) 6037:n 6033:p 6029:p 6025:n 6021:p 6012:) 6008:n 6000:p 5992:) 5988:p 5984:p 5976:) 5972:p 5968:p 5960:) 5956:p 5952:p 5948:p 5944:p 5936:) 5932:p 5928:p 5924:p 5920:p 5912:) 5908:p 5904:p 5891:k 5687:) 5683:( 5629:) 5626:⌋ 5623:A 5620:⌊ 5612:) 5608:b 5604:b 5602:( 5595:) 5586:) 5583:y 5579:x 5571:) 5568:y 5564:x 5560:y 5556:x 5548:) 5544:n 5536:) 5532:n 5524:) 5515:) 5512:y 5508:x 5500:) 5491:) 5487:n 5485:4 5478:) 5473:n 5471:p 5463:) 5458:n 5456:p 5448:) 5444:n 5436:) 5432:k 5416:) 5407:) 5398:) 5371:e 5364:t 5357:v 3556:a 3437:e 3430:t 3423:v 3409:. 3355:. 3324:. 3288:. 3269:. 3226:. 3220:. 3180:n 3162:. 3156:: 3141:. 3108:. 3050:. 3046:: 3036:: 3013:. 2951:1 2939:) 2933:( 2927:= 2921:) 2915:( 2909:. 2903:: 2885:1 2867:= 2858:: 2849:) 2843:: 2837:( 2813:= 2807:) 2804:2 2801:, 2795:% 2789:( 2777:: 2774:0 2762:0 2759:= 2744:= 2738:: 2732:, 2726:( 2689:= 2686:b 2666:2 2663:= 2660:p 2592:× 2584:7 2507:b 2483:b 2463:b 2439:n 2423:n 2419:n 2362:b 2359:, 2356:2 2352:F 2321:b 2318:, 2315:2 2311:F 2287:= 2284:b 2245:b 2242:, 2239:2 2235:F 2204:b 2201:, 2198:2 2194:F 2173:6 2170:= 2167:b 2133:b 2130:, 2127:2 2123:F 2096:b 2093:, 2090:2 2086:F 2065:4 2062:= 2059:b 2040:b 2022:× 2020:5 2006:b 1986:b 1958:: 1935:b 1913:b 1893:b 1871:n 1858:( 1844:n 1840:b 1819:n 1799:b 1779:b 1756:1 1753:= 1748:2 1744:0 1740:+ 1735:2 1731:1 1727:= 1724:) 1719:6 1711:( 1706:6 1703:, 1700:2 1696:F 1692:= 1689:) 1686:6 1683:( 1678:6 1675:, 1672:2 1668:F 1664:= 1661:) 1655:( 1650:3 1645:6 1642:, 1639:2 1635:F 1613:6 1610:= 1605:2 1601:2 1597:+ 1592:2 1588:1 1584:+ 1579:2 1575:1 1571:= 1568:) 1563:6 1555:( 1550:6 1547:, 1544:2 1540:F 1536:= 1533:) 1527:( 1522:6 1519:, 1516:2 1512:F 1508:= 1505:) 1499:( 1494:2 1489:6 1486:, 1483:2 1479:F 1454:= 1449:2 1445:5 1441:+ 1436:2 1432:3 1428:+ 1423:2 1419:3 1415:+ 1410:2 1406:1 1402:= 1399:) 1394:6 1386:( 1381:6 1378:, 1375:2 1371:F 1367:= 1364:) 1358:( 1353:6 1350:, 1347:2 1343:F 1316:1 1313:= 1308:2 1304:0 1300:+ 1295:2 1291:0 1287:+ 1282:2 1278:1 1274:= 1271:) 1265:( 1257:, 1254:2 1250:F 1246:= 1243:) 1237:( 1232:4 1224:, 1221:2 1217:F 1192:= 1187:2 1183:8 1179:+ 1174:2 1170:6 1166:= 1163:) 1157:( 1149:, 1146:2 1142:F 1138:= 1135:) 1129:( 1124:3 1116:, 1113:2 1109:F 1084:= 1079:2 1075:2 1071:+ 1066:2 1062:8 1058:= 1055:) 1049:( 1041:, 1038:2 1034:F 1030:= 1027:) 1021:( 1016:2 1008:, 1005:2 1001:F 976:= 971:2 967:9 963:+ 958:2 954:1 950:= 947:) 941:( 933:, 930:2 926:F 899:b 877:b 874:, 871:2 867:F 842:b 820:b 817:, 814:2 810:F 785:j 763:j 758:b 755:, 752:2 748:F 727:1 724:= 721:) 718:n 715:( 710:j 705:b 702:, 699:2 695:F 674:j 654:b 634:n 614:1 608:b 596:. 582:p 576:) 569:i 565:b 556:i 552:b 543:n 533:1 530:+ 527:i 523:b 514:n 508:( 496:n 487:b 474:0 471:= 468:i 460:= 457:) 454:n 451:( 446:b 443:, 440:p 436:F 409:n 356:2 353:= 350:p 326:b 307:- 295:b 264:4 261:= 256:2 252:0 248:+ 243:2 239:2 215:= 210:2 206:6 202:+ 197:2 193:1 169:= 164:2 160:4 139:1 136:= 131:2 127:0 123:+ 118:2 114:1 90:= 85:2 81:3 77:+ 72:2 68:1 20:)

Index

Happy prime
Harshad number

number theory
natural number
number base
perfect digital invariant function
Reg Allenby
pure mathematics
Leeds University
Guy 2004
Perfect digital invariant
perfect digital invariant function
iteration
nontrivial perfect digital invariant
natural density
base 2
base 4
(more unsolved problems in mathematics)
base 2
base 4
preperiodic points
base 4
A007770
OEIS
A124095
OEIS
prime
base 2
base 4

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