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1 − 1 + 2 − 6 + 24 − 120 + ⋯

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40: 1869: 2178: 872: 672: 367: 1477: 527: 1197: 1027: 1297: 867:{\displaystyle {\begin{aligned}\sum _{k=0}^{\infty }(-1)^{k}k!&=\int _{0}^{\infty }{\frac {e^{-x}}{1+x}}\,dx\\&=eE_{1}(1)\approx 0.596\,347\,362\,323\,194\,074\,341\,078\,499\,369\ldots \end{aligned}}} 677: 163: 218: 2060: 644: 603: 1318:). Euler argues (more or less) that since the formal series and the integral both describe the same solution to the differential equations, they should equal each other at 1350: 566: 2050: 1082: 1703: 1342: 664: 2143: 1984: 378: 1090: 1994: 914: 1215: 1989: 2158: 1749: 1696: 2138: 2040: 2030: 1519: 1514: 83: 61: 2148: 2153: 2055: 1689: 2181: 2163: 105: 2035: 2025: 2015: 1509: 1504: 1493: 2045: 2202: 362:{\displaystyle \sum _{k=0}^{\infty }(-1)^{k}k!=\sum _{k=0}^{\infty }(-1)^{k}\int _{0}^{\infty }x^{k}e^{-x}\,dx.} 54: 48: 2130: 1952: 1792: 1739: 1590: 65: 208:
that are alternately added or subtracted. One way to assign a value to this divergent series is by using
184:
with alternating signs. Despite being divergent, it can be assigned a value of approximately 0.596347 by
1999: 1744: 1488: 606: 28: 612: 571: 2110: 1947: 1716: 1635: 1560: 1307: 1303: 889: 1595: 2090: 1957: 372:
If summation and integration are interchanged (ignoring that neither side converges), one obtains:
1472:{\displaystyle \sum _{n=1}^{\infty }(-1)^{n+1}(n-1)!=e\int _{1}^{\infty }{\frac {e^{-u}}{u}}\,du.} 1931: 1916: 1888: 1868: 1807: 1651: 1608: 1550: 201: 2020: 1498: 2120: 1921: 1893: 1847: 1837: 1817: 1802: 897: 535: 2105: 1926: 1852: 1842: 1822: 1724: 1671: 1643: 1600: 169: 17: 1883: 1812: 209: 185: 1321: 1639: 1564: 1542: 2115: 2100: 2095: 1774: 1759: 1538: 649: 197: 181: 173: 2196: 2080: 1754: 1675: 1655: 1620: 1647: 2085: 1827: 1769: 522:{\displaystyle \sum _{k=0}^{\infty }(-1)^{k}k!=\int _{0}^{\infty }\lefte^{-x}\,dx.} 1662:
Leah, P. J.; Barbeau, E. J. (May 1976), "Euler's 1760 paper on divergent series",
1832: 1779: 1764: 893: 205: 177: 1192:{\displaystyle x(t)=\sum _{n=1}^{\infty }(-1)^{n+1}{\frac {(n-1)!}{t^{n}}}} 1712: 1681: 1612: 1209:
On the other hand, the system of differential equations has a solution
1022:{\displaystyle {\dot {x}}(t)=x(t)-y(t),\qquad {\dot {y}}(t)=-y(t)^{2}} 1292:{\displaystyle x(t)=e^{t}\int _{t}^{\infty }{\frac {e^{-u}}{u}}\,du.} 1604: 1555: 1685: 204:
to assign a finite value to the series. The series is a sum of
33: 1581:
Kline, Morris (November 1983), "Euler and Infinite Series",
27:
For a related alternating partial sum of factorials, see
1081:, and substituting it into the first equation gives a 908:
Consider the coupled system of differential equations
617: 576: 96:
Divergent series that can be summed by Borel summation
2061:
1/2 + 1/3 + 1/5 + 1/7 + 1/11 + ⋯ (inverses of primes)
2051:
1 − 1 + 2 − 6 + 24 − 120 + ⋯ (alternating factorials)
1547:
Novi Commentarii Academiae Scientiarum Petropolitanae
1353: 1324: 1218: 1093: 917: 675: 652: 615: 574: 538: 381: 221: 108: 532:
The summation in the square brackets converges when
2129: 2073: 2008: 1977: 1970: 1940: 1909: 1902: 1876: 1788: 1732: 1723: 1471: 1336: 1291: 1191: 1021: 866: 666:leads to a convergent integral for the summation: 658: 638: 597: 560: 521: 361: 157: 158:{\displaystyle \sum _{k=0}^{\infty }(-1)^{k}k!} 1306:, the formal power series is recovered as an 1032:where dots denote derivatives with respect to 1697: 1621:"Euler and mathematical methods in mechanics" 8: 2144:Hypergeometric function of a matrix argument 2000:1 + 1/2 + 1/3 + ... (Riemann zeta function) 1974: 1906: 1729: 1704: 1690: 1682: 2056:1 + 1/2 + 1/3 + 1/4 + ⋯ (harmonic series) 1594: 1554: 1459: 1445: 1439: 1433: 1428: 1388: 1369: 1358: 1352: 1323: 1279: 1265: 1259: 1253: 1248: 1238: 1217: 1181: 1155: 1143: 1124: 1113: 1092: 1013: 974: 973: 919: 918: 916: 853: 849: 845: 841: 837: 833: 829: 825: 821: 800: 776: 754: 748: 742: 737: 714: 695: 684: 676: 674: 651: 616: 614: 575: 573: 547: 539: 537: 509: 500: 485: 466: 455: 440: 435: 416: 397: 386: 380: 349: 340: 330: 320: 315: 305: 286: 275: 256: 237: 226: 220: 143: 124: 113: 107: 84:Learn how and when to remove this message 1039:The solution with stable equilibrium at 47:This article includes a list of general 1530: 7: 904:Connection to differential equations 196:This series was first considered by 2021:1 − 1 + 1 − 1 + ⋯ (Grandi's series) 896:of the series, and is equal to the 1434: 1370: 1254: 1125: 743: 696: 467: 441: 398: 321: 287: 238: 125: 53:it lacks sufficient corresponding 25: 2139:Generalized hypergeometric series 1206:(1) is precisely Euler's series. 639:{\displaystyle {\tfrac {1}{1+x}}} 598:{\displaystyle {\tfrac {1}{1+x}}} 2177: 2176: 2149:Lauricella hypergeometric series 1867: 38: 2159:Riemann's differential equation 1648:10.1070/rm2007v062n04abeh004427 1545:[On divergent series]. 972: 1412: 1400: 1385: 1375: 1228: 1222: 1170: 1158: 1140: 1130: 1103: 1097: 1010: 1003: 991: 985: 966: 960: 951: 945: 936: 930: 812: 806: 711: 701: 568:, and for those values equals 548: 540: 482: 472: 413: 403: 302: 292: 253: 243: 140: 130: 1: 2154:Modular hypergeometric series 1995:1/4 + 1/16 + 1/64 + 1/256 + ⋯ 1676:10.1016/0315-0860(76)90030-6 1628:Russian Mathematical Surveys 892:. This is by definition the 212:, where one formally writes 18:1 − 1 + 2 − 6 + 24 − 120 + … 2164:Theta hypergeometric series 1543:"De seriebus divergentibus" 2219: 2046:Infinite arithmetic series 1990:1/2 + 1/4 + 1/8 + 1/16 + ⋯ 1985:1/2 − 1/4 + 1/8 − 1/16 + ⋯ 26: 2172: 1865: 192:Euler and Borel summation 1308:asymptotic approximation 561:{\displaystyle |x|<1} 1877:Properties of sequences 1310:to this expression for 68:more precise citations. 1740:Arithmetic progression 1619:Kozlov, V. V. (2007), 1473: 1374: 1338: 1293: 1193: 1129: 1083:formal series solution 1023: 868: 700: 660: 640: 599: 562: 523: 471: 402: 363: 291: 242: 172:, first considered by 159: 129: 2131:Hypergeometric series 1745:Geometric progression 1489:Alternating factorial 1474: 1354: 1339: 1294: 1194: 1109: 1024: 869: 680: 661: 646:to all positive real 641: 607:analytic continuation 600: 563: 524: 451: 382: 364: 271: 222: 160: 109: 29:Alternating factorial 2111:Trigonometric series 1903:Properties of series 1750:Harmonic progression 1664:Historia Mathematica 1583:Mathematics Magazine 1351: 1322: 1304:integrating by parts 1216: 1091: 915: 890:exponential integral 673: 650: 613: 572: 536: 379: 219: 106: 2091:Formal power series 1640:2007RuMaS..62..639K 1565:2018arXiv180802841E 1438: 1337:{\displaystyle t=1} 1258: 1055: → ∞ has 747: 445: 325: 202:summability methods 1889:Monotonic function 1808:Fibonacci sequence 1469: 1424: 1334: 1289: 1244: 1189: 1019: 864: 862: 733: 656: 636: 634: 595: 593: 558: 519: 431: 359: 311: 155: 2190: 2189: 2121:Generating series 2069: 2068: 2041:1 − 2 + 4 − 8 + ⋯ 2036:1 + 2 + 4 + 8 + ⋯ 2031:1 − 2 + 3 − 4 + ⋯ 2026:1 + 2 + 3 + 4 + ⋯ 2016:1 + 1 + 1 + 1 + ⋯ 1966: 1965: 1894:Periodic sequence 1863: 1862: 1848:Triangular number 1838:Pentagonal number 1818:Heptagonal number 1803:Complete sequence 1725:Integer sequences 1520:1 − 2 + 4 − 8 + ⋯ 1515:1 − 2 + 3 − 4 + ⋯ 1510:1 + 2 + 4 + 8 + ⋯ 1505:1 + 2 + 3 + 4 + ⋯ 1499:1 − 1 + 1 − 1 + ⋯ 1494:1 + 1 + 1 + 1 + ⋯ 1457: 1277: 1187: 982: 927: 898:Gompertz constant 774: 659:{\displaystyle x} 633: 592: 99:In mathematics, 94: 93: 86: 16:(Redirected from 2210: 2203:Divergent series 2180: 2179: 2106:Dirichlet series 1975: 1907: 1871: 1843:Polygonal number 1823:Hexagonal number 1796: 1730: 1706: 1699: 1692: 1683: 1678: 1658: 1625: 1615: 1598: 1569: 1568: 1558: 1535: 1478: 1476: 1475: 1470: 1458: 1453: 1452: 1440: 1437: 1432: 1399: 1398: 1373: 1368: 1343: 1341: 1340: 1335: 1302:By successively 1298: 1296: 1295: 1290: 1278: 1273: 1272: 1260: 1257: 1252: 1243: 1242: 1198: 1196: 1195: 1190: 1188: 1186: 1185: 1176: 1156: 1154: 1153: 1128: 1123: 1080: 1078: 1077: 1072: 1069: 1050: 1028: 1026: 1025: 1020: 1018: 1017: 984: 983: 975: 929: 928: 920: 873: 871: 870: 865: 863: 805: 804: 786: 775: 773: 762: 761: 749: 746: 741: 719: 718: 699: 694: 665: 663: 662: 657: 645: 643: 642: 637: 635: 632: 618: 604: 602: 601: 596: 594: 591: 577: 567: 565: 564: 559: 551: 543: 528: 526: 525: 520: 508: 507: 495: 491: 490: 489: 470: 465: 444: 439: 421: 420: 401: 396: 368: 366: 365: 360: 348: 347: 335: 334: 324: 319: 310: 309: 290: 285: 261: 260: 241: 236: 176:, that sums the 170:divergent series 164: 162: 161: 156: 148: 147: 128: 123: 89: 82: 78: 75: 69: 64:this article by 55:inline citations 42: 41: 34: 21: 2218: 2217: 2213: 2212: 2211: 2209: 2208: 2207: 2193: 2192: 2191: 2186: 2168: 2125: 2074:Kinds of series 2065: 2004: 1971:Explicit series 1962: 1936: 1898: 1884:Cauchy sequence 1872: 1859: 1813:Figurate number 1790: 1784: 1775:Powers of three 1719: 1710: 1661: 1623: 1618: 1605:10.2307/2690371 1596:10.1.1.639.6923 1580: 1577: 1575:Further reading 1572: 1537: 1536: 1532: 1528: 1485: 1441: 1384: 1349: 1348: 1320: 1319: 1261: 1234: 1214: 1213: 1177: 1157: 1139: 1089: 1088: 1073: 1070: 1067: 1066: 1064: 1040: 1009: 913: 912: 906: 883: 861: 860: 796: 784: 783: 763: 750: 726: 710: 671: 670: 648: 647: 622: 611: 610: 581: 570: 569: 534: 533: 496: 481: 450: 446: 412: 377: 376: 336: 326: 301: 252: 217: 216: 210:Borel summation 194: 186:Borel summation 182:natural numbers 139: 104: 103: 97: 90: 79: 73: 70: 60:Please help to 59: 43: 39: 32: 23: 22: 15: 12: 11: 5: 2216: 2214: 2206: 2205: 2195: 2194: 2188: 2187: 2185: 2184: 2173: 2170: 2169: 2167: 2166: 2161: 2156: 2151: 2146: 2141: 2135: 2133: 2127: 2126: 2124: 2123: 2118: 2116:Fourier series 2113: 2108: 2103: 2101:Puiseux series 2098: 2096:Laurent series 2093: 2088: 2083: 2077: 2075: 2071: 2070: 2067: 2066: 2064: 2063: 2058: 2053: 2048: 2043: 2038: 2033: 2028: 2023: 2018: 2012: 2010: 2006: 2005: 2003: 2002: 1997: 1992: 1987: 1981: 1979: 1972: 1968: 1967: 1964: 1963: 1961: 1960: 1955: 1950: 1944: 1942: 1938: 1937: 1935: 1934: 1929: 1924: 1919: 1913: 1911: 1904: 1900: 1899: 1897: 1896: 1891: 1886: 1880: 1878: 1874: 1873: 1866: 1864: 1861: 1860: 1858: 1857: 1856: 1855: 1845: 1840: 1835: 1830: 1825: 1820: 1815: 1810: 1805: 1799: 1797: 1786: 1785: 1783: 1782: 1777: 1772: 1767: 1762: 1757: 1752: 1747: 1742: 1736: 1734: 1727: 1721: 1720: 1711: 1709: 1708: 1701: 1694: 1686: 1680: 1679: 1670:(2): 141–160, 1659: 1634:(4): 639–661, 1616: 1589:(5): 307–313, 1576: 1573: 1571: 1570: 1549:(5): 205–237. 1529: 1527: 1524: 1523: 1522: 1517: 1512: 1507: 1502: 1496: 1491: 1484: 1481: 1480: 1479: 1468: 1465: 1462: 1456: 1451: 1448: 1444: 1436: 1431: 1427: 1423: 1420: 1417: 1414: 1411: 1408: 1405: 1402: 1397: 1394: 1391: 1387: 1383: 1380: 1377: 1372: 1367: 1364: 1361: 1357: 1333: 1330: 1327: 1300: 1299: 1288: 1285: 1282: 1276: 1271: 1268: 1264: 1256: 1251: 1247: 1241: 1237: 1233: 1230: 1227: 1224: 1221: 1200: 1199: 1184: 1180: 1175: 1172: 1169: 1166: 1163: 1160: 1152: 1149: 1146: 1142: 1138: 1135: 1132: 1127: 1122: 1119: 1116: 1112: 1108: 1105: 1102: 1099: 1096: 1063:) =  1030: 1029: 1016: 1012: 1008: 1005: 1002: 999: 996: 993: 990: 987: 981: 978: 971: 968: 965: 962: 959: 956: 953: 950: 947: 944: 941: 938: 935: 932: 926: 923: 905: 902: 881: 875: 874: 859: 856: 852: 848: 844: 840: 836: 832: 828: 824: 820: 817: 814: 811: 808: 803: 799: 795: 792: 789: 787: 785: 782: 779: 772: 769: 766: 760: 757: 753: 745: 740: 736: 732: 729: 727: 725: 722: 717: 713: 709: 706: 703: 698: 693: 690: 687: 683: 679: 678: 655: 631: 628: 625: 621: 590: 587: 584: 580: 557: 554: 550: 546: 542: 530: 529: 518: 515: 512: 506: 503: 499: 494: 488: 484: 480: 477: 474: 469: 464: 461: 458: 454: 449: 443: 438: 434: 430: 427: 424: 419: 415: 411: 408: 405: 400: 395: 392: 389: 385: 370: 369: 358: 355: 352: 346: 343: 339: 333: 329: 323: 318: 314: 308: 304: 300: 297: 294: 289: 284: 281: 278: 274: 270: 267: 264: 259: 255: 251: 248: 245: 240: 235: 232: 229: 225: 200:, who applied 193: 190: 166: 165: 154: 151: 146: 142: 138: 135: 132: 127: 122: 119: 116: 112: 95: 92: 91: 46: 44: 37: 24: 14: 13: 10: 9: 6: 4: 3: 2: 2215: 2204: 2201: 2200: 2198: 2183: 2175: 2174: 2171: 2165: 2162: 2160: 2157: 2155: 2152: 2150: 2147: 2145: 2142: 2140: 2137: 2136: 2134: 2132: 2128: 2122: 2119: 2117: 2114: 2112: 2109: 2107: 2104: 2102: 2099: 2097: 2094: 2092: 2089: 2087: 2084: 2082: 2081:Taylor series 2079: 2078: 2076: 2072: 2062: 2059: 2057: 2054: 2052: 2049: 2047: 2044: 2042: 2039: 2037: 2034: 2032: 2029: 2027: 2024: 2022: 2019: 2017: 2014: 2013: 2011: 2007: 2001: 1998: 1996: 1993: 1991: 1988: 1986: 1983: 1982: 1980: 1976: 1973: 1969: 1959: 1956: 1954: 1951: 1949: 1946: 1945: 1943: 1939: 1933: 1930: 1928: 1925: 1923: 1920: 1918: 1915: 1914: 1912: 1908: 1905: 1901: 1895: 1892: 1890: 1887: 1885: 1882: 1881: 1879: 1875: 1870: 1854: 1851: 1850: 1849: 1846: 1844: 1841: 1839: 1836: 1834: 1831: 1829: 1826: 1824: 1821: 1819: 1816: 1814: 1811: 1809: 1806: 1804: 1801: 1800: 1798: 1794: 1787: 1781: 1778: 1776: 1773: 1771: 1770:Powers of two 1768: 1766: 1763: 1761: 1758: 1756: 1755:Square number 1753: 1751: 1748: 1746: 1743: 1741: 1738: 1737: 1735: 1731: 1728: 1726: 1722: 1718: 1714: 1707: 1702: 1700: 1695: 1693: 1688: 1687: 1684: 1677: 1673: 1669: 1665: 1660: 1657: 1653: 1649: 1645: 1641: 1637: 1633: 1629: 1622: 1617: 1614: 1610: 1606: 1602: 1597: 1592: 1588: 1584: 1579: 1578: 1574: 1566: 1562: 1557: 1552: 1548: 1544: 1540: 1534: 1531: 1525: 1521: 1518: 1516: 1513: 1511: 1508: 1506: 1503: 1500: 1497: 1495: 1492: 1490: 1487: 1486: 1482: 1466: 1463: 1460: 1454: 1449: 1446: 1442: 1429: 1425: 1421: 1418: 1415: 1409: 1406: 1403: 1395: 1392: 1389: 1381: 1378: 1365: 1362: 1359: 1355: 1347: 1346: 1345: 1331: 1328: 1325: 1317: 1313: 1309: 1305: 1286: 1283: 1280: 1274: 1269: 1266: 1262: 1249: 1245: 1239: 1235: 1231: 1225: 1219: 1212: 1211: 1210: 1207: 1205: 1182: 1178: 1173: 1167: 1164: 1161: 1150: 1147: 1144: 1136: 1133: 1120: 1117: 1114: 1110: 1106: 1100: 1094: 1087: 1086: 1085: 1084: 1076: 1062: 1058: 1054: 1048: 1044: 1037: 1035: 1014: 1006: 1000: 997: 994: 988: 979: 976: 969: 963: 957: 954: 948: 942: 939: 933: 924: 921: 911: 910: 909: 903: 901: 899: 895: 891: 887: 880: 857: 854: 850: 846: 842: 838: 834: 830: 826: 822: 818: 815: 809: 801: 797: 793: 790: 788: 780: 777: 770: 767: 764: 758: 755: 751: 738: 734: 730: 728: 723: 720: 715: 707: 704: 691: 688: 685: 681: 669: 668: 667: 653: 629: 626: 623: 619: 608: 588: 585: 582: 578: 555: 552: 544: 516: 513: 510: 504: 501: 497: 492: 486: 478: 475: 462: 459: 456: 452: 447: 436: 432: 428: 425: 422: 417: 409: 406: 393: 390: 387: 383: 375: 374: 373: 356: 353: 350: 344: 341: 337: 331: 327: 316: 312: 306: 298: 295: 282: 279: 276: 272: 268: 265: 262: 257: 249: 246: 233: 230: 227: 223: 215: 214: 213: 211: 207: 203: 199: 191: 189: 187: 183: 179: 175: 171: 152: 149: 144: 136: 133: 120: 117: 114: 110: 102: 101: 100: 88: 85: 77: 67: 63: 57: 56: 50: 45: 36: 35: 30: 19: 2086:Power series 1828:Lucas number 1780:Powers of 10 1760:Cubic number 1667: 1663: 1631: 1627: 1586: 1582: 1546: 1533: 1315: 1311: 1301: 1208: 1203: 1201: 1074: 1060: 1056: 1052: 1046: 1042: 1038: 1033: 1031: 907: 885: 878: 876: 531: 371: 195: 167: 98: 80: 74:January 2021 71: 52: 1953:Conditional 1941:Convergence 1932:Telescoping 1917:Alternating 1833:Pell number 66:introducing 1978:Convergent 1922:Convergent 1556:1808.02841 1526:References 1501:(Grandi's) 206:factorials 178:factorials 49:references 2009:Divergent 1927:Divergent 1789:Advanced 1765:Factorial 1713:Sequences 1656:250892576 1591:CiteSeerX 1539:Euler, L. 1447:− 1435:∞ 1426:∫ 1407:− 1379:− 1371:∞ 1356:∑ 1344:, giving 1267:− 1255:∞ 1246:∫ 1165:− 1134:− 1126:∞ 1111:∑ 1049:) = (0,0) 998:− 980:˙ 955:− 925:˙ 894:Borel sum 888:) is the 858:… 816:≈ 756:− 744:∞ 735:∫ 705:− 697:∞ 682:∑ 502:− 476:− 468:∞ 453:∑ 442:∞ 433:∫ 407:− 399:∞ 384:∑ 342:− 322:∞ 313:∫ 296:− 288:∞ 273:∑ 247:− 239:∞ 224:∑ 134:− 126:∞ 111:∑ 2197:Category 2182:Category 1948:Absolute 1541:(1760). 1483:See also 1202:Observe 1958:Uniform 1636:Bibcode 1613:2690371 1561:Bibcode 1079:⁠ 1065:⁠ 180:of the 62:improve 1910:Series 1717:series 1654:  1611:  1593:  877:where 605:. The 51:, but 1853:array 1733:Basic 1652:S2CID 1624:(PDF) 1609:JSTOR 1551:arXiv 819:0.596 198:Euler 174:Euler 168:is a 1793:list 1715:and 553:< 1672:doi 1644:doi 1601:doi 1051:as 855:369 851:499 847:078 843:341 839:074 835:194 831:323 827:362 823:347 609:of 2199:: 1666:, 1650:, 1642:, 1632:62 1630:, 1626:, 1607:, 1599:, 1587:56 1585:, 1559:. 1036:. 900:. 188:. 1795:) 1791:( 1705:e 1698:t 1691:v 1674:: 1668:3 1646:: 1638:: 1603:: 1567:. 1563:: 1553:: 1467:. 1464:u 1461:d 1455:u 1450:u 1443:e 1430:1 1422:e 1419:= 1416:! 1413:) 1410:1 1404:n 1401:( 1396:1 1393:+ 1390:n 1386:) 1382:1 1376:( 1366:1 1363:= 1360:n 1332:1 1329:= 1326:t 1316:t 1314:( 1312:x 1287:. 1284:u 1281:d 1275:u 1270:u 1263:e 1250:t 1240:t 1236:e 1232:= 1229:) 1226:t 1223:( 1220:x 1204:x 1183:n 1179:t 1174:! 1171:) 1168:1 1162:n 1159:( 1151:1 1148:+ 1145:n 1141:) 1137:1 1131:( 1121:1 1118:= 1115:n 1107:= 1104:) 1101:t 1098:( 1095:x 1075:t 1071:/ 1068:1 1061:t 1059:( 1057:y 1053:t 1047:y 1045:, 1043:x 1041:( 1034:t 1015:2 1011:) 1007:t 1004:( 1001:y 995:= 992:) 989:t 986:( 977:y 970:, 967:) 964:t 961:( 958:y 952:) 949:t 946:( 943:x 940:= 937:) 934:t 931:( 922:x 886:z 884:( 882:1 879:E 813:) 810:1 807:( 802:1 798:E 794:e 791:= 781:x 778:d 771:x 768:+ 765:1 759:x 752:e 739:0 731:= 724:! 721:k 716:k 712:) 708:1 702:( 692:0 689:= 686:k 654:x 630:x 627:+ 624:1 620:1 589:x 586:+ 583:1 579:1 556:1 549:| 545:x 541:| 517:. 514:x 511:d 505:x 498:e 493:] 487:k 483:) 479:x 473:( 463:0 460:= 457:k 448:[ 437:0 429:= 426:! 423:k 418:k 414:) 410:1 404:( 394:0 391:= 388:k 357:. 354:x 351:d 345:x 338:e 332:k 328:x 317:0 307:k 303:) 299:1 293:( 283:0 280:= 277:k 269:= 266:! 263:k 258:k 254:) 250:1 244:( 234:0 231:= 228:k 153:! 150:k 145:k 141:) 137:1 131:( 121:0 118:= 115:k 87:) 81:( 76:) 72:( 58:. 31:. 20:)

Index

1 − 1 + 2 − 6 + 24 − 120 + …
Alternating factorial
references
inline citations
improve
introducing
Learn how and when to remove this message
divergent series
Euler
factorials
natural numbers
Borel summation
Euler
summability methods
factorials
Borel summation
analytic continuation
exponential integral
Borel sum
Gompertz constant
formal series solution
integrating by parts
asymptotic approximation
Alternating factorial
1 + 1 + 1 + 1 + ⋯
1 − 1 + 1 − 1 + ⋯
1 + 2 + 3 + 4 + ⋯
1 + 2 + 4 + 8 + ⋯
1 − 2 + 3 − 4 + ⋯
1 − 2 + 4 − 8 + ⋯

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