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Enumerative combinatorics

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1873: 1434: 951: 1868:{\displaystyle {\begin{aligned}p_{n}&=P(x)={\frac {1-{\sqrt {1-4x}}}{2}}\\&={\frac {1}{2}}-{\frac {1}{2}}{\sqrt {1-4x}}\\&=-{\frac {1}{2}}\sum _{k=0}^{\infty }{{\frac {1}{2}} \choose k}(-4x)^{k}\\&=-{\frac {1}{2}}{{\frac {1}{2}} \choose n}(-4)^{n}\\&={\frac {1}{n}}{2n-2 \choose n-1}\end{aligned}}} 1274:. Putting the above description in words: A plane tree consists of a node to which is attached an arbitrary number of subtrees, each of which is also a plane tree. Using the operation on families of combinatorial structures developed earlier, this translates to a recursive generating function: 1109:
and cycles. A combinatorial structure is composed of atoms. For example, with trees the atoms would be the nodes. The atoms which compose the object can either be labeled or unlabeled. Unlabeled atoms are indistinguishable from each other, while labelled atoms are distinct. Therefore, for a
820: 1122:. There is generally a node called the root, which has no parent node. In plane trees each node can have an arbitrary number of children. In binary trees, a special case of plane trees, each node can have either two or no children. Let 1207: 1439: 946:{\displaystyle {\mbox{Seq}}({\mathcal {F}})=\epsilon \ \cup \ {\mathcal {F}}\ \cup \ {\mathcal {F}}\!\times \!{\mathcal {F}}\ \cup \ {\mathcal {F}}\!\times \!{\mathcal {F}}\!\times \!{\mathcal {F}}\ \cup \cdots } 605: 1087: 610:
Once determined, the generating function yields the information given by the previous approaches. In addition, the various natural operations on generating functions such as addition, multiplication,
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To put the above in words: An empty sequence or a sequence of one element or a sequence of two elements or a sequence of three elements, etc. The generating function would be:
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Often, a complicated closed formula yields little insight into the behavior of the counting function as the number of counted objects grows. In these cases, a simple
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Binary and plane trees are examples of an unlabeled combinatorial structure. Trees consist of nodes linked by edges in such a way that there are no
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generalizes the idea of the pair as defined above. Sequences are arbitrary Cartesian products of a combinatorial object with itself. Formally:
525: 2087: 614:, etc., have a combinatorial significance; this allows one to extend results from one combinatorial problem in order to solve others. 962: 515:. Some common operation on families of combinatorial objects and its effect on the generating function will now be developed. The 1903: 376: 26:
that deals with the number of ways that certain patterns can be formed. Two examples of this type of problem are counting
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combinatorial object consisting of labeled atoms a new object can be formed by simply swapping two or more atoms.
1990: 1280: 516: 2168: 2099: 205: 2174: 1995: 257: 2124: 2017: 283: 1970: 1253: 1125: 649: 625: 341: 109:, and so on. For instance, as shown below, the number of different possible orderings of a deck of 1975: 1955: 1215: 1965: 1950: 1146:
denote the family of all plane trees. Then this family can be recursively defined as follows:
1980: 126: 2045: 1119: 491: 452: 69: 65: 2216: 176: 147: 8: 2052:, Volumes 1 and 2. Elsevier (North-Holland), Amsterdam, and MIT Press, Cambridge, Mass. 1960: 1098: 1097:
The above operations can now be used to enumerate common combinatorial objects including
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Area of combinatorics that deals with the number of ways certain patterns can be formed
1238:
represents the family of objects consisting of one node. This has generating function
2202: 2164: 2136: 2128: 2103: 2095: 2073: 2053: 749: 2022: 2212: 2150: 2013: 2196: 2030: 1202:{\displaystyle {\mathcal {P}}=\{\bullet \}\times \,{\mbox{Seq}}({\mathcal {P}})} 1918: 687: 106: 97: 77: 44: 2227: 2069: 2037: 73: 23: 2192: 2000: 72:, many of the problems that arise in applications have a relatively simple 101:, which can be expressed as a composition of elementary functions such as 2154: 2146: 1899: 1102: 485: 85: 81: 31: 27: 611: 2117: 1106: 102: 811: 600:{\displaystyle F(x)=\sum _{n=0}^{\infty }f_{n}{\frac {x^{n}}{n!}}} 1906:. To get from the fourth to fifth line manipulations using the 34:. More generally, given an infinite collection of finite sets 1082:{\displaystyle 1+F(x)+^{2}+^{3}+\cdots ={\frac {1}{1-F(x)}}.} 519:
is also sometimes used. In this case it would have the form
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are used to describe families of combinatorial objects. Let
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The Crest of the Peacock: Non-European Roots of Mathematics
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An explicit formula for the number of plane trees of size
125:!. The problem of finding a closed formula is known as 1424:
can now be determined by extracting the coefficient of
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and using this to arrive at the desired closed form.
476:
denotes the number of combinatorial objects of size
439:{\displaystyle F(x)=\sum _{n=0}^{\infty }f_{n}x^{n}} 779:{\displaystyle {\mathcal {F}}\times {\mathcal {G}}} 1867: 1410:{\displaystyle P(x)={\frac {1-{\sqrt {1-4x}}}{2}}} 1409: 1332: 1266: 1230: 1201: 1138: 1081: 945: 778: 716: 662: 638: 599: 507: 468: 438: 354: 320: 272: 246: 194: 165: 68:the number of elements in a set is a rather broad 1913:The expression on the last line is equal to the ( 1855: 1823: 1775: 1755: 1701: 1681: 926: 922: 914: 910: 886: 882: 717:{\displaystyle {\mathcal {F}}\cup {\mathcal {G}}} 2225: 47:, enumerative combinatorics seeks to describe a 1904:Newton's generalization of the binomial theorem 480:. The number of combinatorial objects of size 144:approximation may be preferable. A function 2201:(2nd ed.). Boston, MA: Academic Press. 1225: 1219: 1172: 1166: 748:For two combinatorial families as above the 2188:, Wiley & Sons, New York (republished). 2181:, Wiley & Sons, New York (republished). 1333:{\displaystyle P(x)=x\,{\frac {1}{1-P(x)}}} 1092: 80:provides a unified framework for counting 2179:An Introduction to Combinatorial Analysis 1302: 1178: 1113: 317: 2018:Enumerative and Algebraic Combinatorics 330: 2226: 2063: 247:{\displaystyle f(n)/g(n)\rightarrow 1} 51:which counts the number of objects in 362:denote the family of objects and let 129:, and frequently involves deriving a 2191: 2064:Joseph, George Gheverghese (1994) . 273:{\displaystyle n\rightarrow \infty } 370:) be its generating function. Then 13: 1827: 1759: 1685: 1673: 1259: 1191: 1158: 1131: 929: 917: 905: 889: 877: 861: 836: 771: 761: 709: 699: 655: 631: 622:Given two combinatorial families, 560: 411: 347: 267: 173:is an asymptotic approximation to 14: 2245: 1250:) denote the generating function 1908:generalized binomial coefficient 321:{\displaystyle f(n)\sim g(n).\,} 95:The simplest such functions are 1991:Method of distinguished element 1898:). The series expansion of the 1886:) refers to the coefficient of 517:exponential generating function 1791: 1781: 1720: 1707: 1654: 1641: 1589: 1576: 1560: 1547: 1503: 1490: 1484: 1478: 1472: 1459: 1370: 1364: 1324: 1318: 1293: 1287: 1267:{\displaystyle {\mathcal {P}}} 1196: 1186: 1139:{\displaystyle {\mathcal {P}}} 1070: 1064: 1031: 1027: 1021: 1015: 1003: 999: 993: 987: 981: 975: 841: 831: 663:{\displaystyle {\mathcal {G}}} 639:{\displaystyle {\mathcal {F}}} 538: 532: 389: 383: 355:{\displaystyle {\mathcal {F}}} 311: 305: 296: 290: 264: 238: 235: 229: 218: 212: 189: 183: 160: 154: 1: 2007: 1986:Inclusion–exclusion principle 2086:Loehr, Nicholas A. (2011). 1231:{\displaystyle \{\bullet \}} 805: 752:(pair) of the two families ( 7: 1943: 10: 2250: 2125:Cambridge University Press 2032:A Combinatorial Miscellany 786:) has generating function 724:) has generating function 670:with generating functions 484:is therefore given by the 2234:Enumerative combinatorics 2156:Combinatorial Enumeration 2119:Enumerative Combinatorics 2050:Handbook of Combinatorics 1996:Pólya enumeration theorem 1971:Combinatorial game theory 280:. In this case, we write 20:Enumerative combinatorics 2186:Combinatorial Identities 2068:(2nd ed.). London: 1976:Combinatorial principles 1956:Asymptotic combinatorics 1093:Combinatorial structures 743: 617: 2198:Generatingfunctionology 2088:Bijective Combinatorics 1966:Combinatorial explosion 1951:Algebraic combinatorics 2184:Riordan, John (1968). 1917: − 1) 1869: 1677: 1411: 1334: 1268: 1232: 1203: 1140: 1114:Binary and plane trees 1083: 947: 780: 718: 664: 640: 601: 564: 509: 470: 440: 415: 356: 322: 274: 248: 196: 167: 1981:Combinatorial species 1870: 1657: 1412: 1335: 1269: 1233: 1204: 1141: 1084: 948: 781: 719: 690:of the two families ( 665: 641: 602: 544: 510: 508:{\displaystyle x^{n}} 471: 469:{\displaystyle f_{n}} 441: 395: 357: 323: 275: 249: 197: 168: 127:algebraic enumeration 1878:Note: The notation 1435: 1358: 1281: 1254: 1216: 1153: 1126: 963: 821: 756: 694: 686:) respectively, the 650: 626: 526: 492: 453: 377: 342: 336:Generating functions 331:Generating functions 284: 258: 206: 195:{\displaystyle f(n)} 177: 166:{\displaystyle g(n)} 148: 70:mathematical problem 2114:Stanley, Richard P. 2027:Stanley, Richard P. 135:generating function 131:recurrence relation 2161:Dover Publications 1865: 1863: 1407: 1343:After solving for 1330: 1264: 1228: 1199: 1184: 1136: 1079: 943: 829: 776: 714: 660: 636: 597: 505: 466: 436: 352: 318: 270: 244: 192: 163: 2151:Jackson, David M. 2121:, Volumes 1 and 2 2038:Graham, Ronald L. 2014:Zeilberger, Doron 1853: 1818: 1773: 1768: 1750: 1699: 1694: 1639: 1616: 1600: 1571: 1535: 1529: 1405: 1399: 1328: 1183: 1074: 936: 902: 896: 874: 868: 858: 852: 828: 750:Cartesian product 595: 76:description. The 49:counting function 2241: 2220: 2193:Wilf, Herbert S. 2083: 1961:Burnside's lemma 1874: 1872: 1871: 1866: 1864: 1860: 1859: 1858: 1852: 1841: 1826: 1819: 1811: 1803: 1799: 1798: 1780: 1779: 1778: 1769: 1761: 1758: 1751: 1743: 1732: 1728: 1727: 1706: 1705: 1704: 1695: 1687: 1684: 1676: 1671: 1653: 1652: 1640: 1632: 1621: 1617: 1603: 1601: 1593: 1588: 1587: 1572: 1564: 1559: 1558: 1540: 1536: 1531: 1530: 1516: 1507: 1502: 1501: 1471: 1470: 1451: 1450: 1416: 1414: 1413: 1408: 1406: 1401: 1400: 1386: 1377: 1339: 1337: 1336: 1331: 1329: 1327: 1304: 1273: 1271: 1270: 1265: 1263: 1262: 1237: 1235: 1234: 1229: 1208: 1206: 1205: 1200: 1195: 1194: 1185: 1181: 1162: 1161: 1145: 1143: 1142: 1137: 1135: 1134: 1088: 1086: 1085: 1080: 1075: 1073: 1050: 1039: 1038: 1011: 1010: 952: 950: 949: 944: 934: 933: 932: 921: 920: 909: 908: 900: 894: 893: 892: 881: 880: 872: 866: 865: 864: 856: 850: 840: 839: 830: 826: 785: 783: 782: 777: 775: 774: 765: 764: 723: 721: 720: 715: 713: 712: 703: 702: 669: 667: 666: 661: 659: 658: 645: 643: 642: 637: 635: 634: 606: 604: 603: 598: 596: 594: 586: 585: 576: 574: 573: 563: 558: 514: 512: 511: 506: 504: 503: 475: 473: 472: 467: 465: 464: 445: 443: 442: 437: 435: 434: 425: 424: 414: 409: 361: 359: 358: 353: 351: 350: 327: 325: 324: 319: 279: 277: 276: 271: 253: 251: 250: 245: 225: 201: 199: 198: 193: 172: 170: 169: 164: 2249: 2248: 2244: 2243: 2242: 2240: 2239: 2238: 2224: 2223: 2209: 2147:Goulden, Ian P. 2116:(1997, 1999). 2080: 2048:, eds. (1996). 2023:Björner, Anders 2010: 2005: 1946: 1939: 1929: 1862: 1861: 1854: 1842: 1828: 1822: 1821: 1820: 1810: 1801: 1800: 1794: 1790: 1774: 1760: 1754: 1753: 1752: 1742: 1730: 1729: 1723: 1719: 1700: 1686: 1680: 1679: 1678: 1672: 1661: 1648: 1644: 1631: 1619: 1618: 1602: 1592: 1583: 1579: 1563: 1554: 1550: 1538: 1537: 1515: 1508: 1506: 1497: 1493: 1466: 1462: 1452: 1446: 1442: 1438: 1436: 1433: 1432: 1385: 1378: 1376: 1359: 1356: 1355: 1308: 1303: 1282: 1279: 1278: 1258: 1257: 1255: 1252: 1251: 1217: 1214: 1213: 1190: 1189: 1179: 1157: 1156: 1154: 1151: 1150: 1130: 1129: 1127: 1124: 1123: 1116: 1095: 1054: 1049: 1034: 1030: 1006: 1002: 964: 961: 960: 928: 927: 916: 915: 904: 903: 888: 887: 876: 875: 860: 859: 835: 834: 824: 822: 819: 818: 808: 770: 769: 760: 759: 757: 754: 753: 746: 708: 707: 698: 697: 695: 692: 691: 654: 653: 651: 648: 647: 630: 629: 627: 624: 623: 620: 612:differentiation 587: 581: 577: 575: 569: 565: 559: 548: 527: 524: 523: 499: 495: 493: 490: 489: 460: 456: 454: 451: 450: 430: 426: 420: 416: 410: 399: 378: 375: 374: 346: 345: 343: 340: 339: 333: 285: 282: 281: 259: 256: 255: 221: 207: 204: 203: 178: 175: 174: 149: 146: 145: 98:closed formulas 59: 45:natural numbers 43:indexed by the 42: 17: 12: 11: 5: 2247: 2237: 2236: 2222: 2221: 2207: 2189: 2182: 2172: 2144: 2111: 2108:978-1439848845 2084: 2078: 2061: 2046:Lovász, László 2035: 2020: 2009: 2006: 2004: 2003: 1998: 1993: 1988: 1983: 1978: 1973: 1968: 1963: 1958: 1953: 1947: 1945: 1942: 1934: 1925: 1919:Catalan number 1876: 1875: 1857: 1851: 1848: 1845: 1840: 1837: 1834: 1831: 1825: 1817: 1814: 1809: 1806: 1804: 1802: 1797: 1793: 1789: 1786: 1783: 1777: 1772: 1767: 1764: 1757: 1749: 1746: 1741: 1738: 1735: 1733: 1731: 1726: 1722: 1718: 1715: 1712: 1709: 1703: 1698: 1693: 1690: 1683: 1675: 1670: 1667: 1664: 1660: 1656: 1651: 1647: 1643: 1638: 1635: 1630: 1627: 1624: 1622: 1620: 1615: 1612: 1609: 1606: 1599: 1596: 1591: 1586: 1582: 1578: 1575: 1570: 1567: 1562: 1557: 1553: 1549: 1546: 1543: 1541: 1539: 1534: 1528: 1525: 1522: 1519: 1514: 1511: 1505: 1500: 1496: 1492: 1489: 1486: 1483: 1480: 1477: 1474: 1469: 1465: 1461: 1458: 1455: 1453: 1449: 1445: 1441: 1440: 1418: 1417: 1404: 1398: 1395: 1392: 1389: 1384: 1381: 1375: 1372: 1369: 1366: 1363: 1341: 1340: 1326: 1323: 1320: 1317: 1314: 1311: 1307: 1301: 1298: 1295: 1292: 1289: 1286: 1261: 1227: 1224: 1221: 1210: 1209: 1198: 1193: 1188: 1177: 1174: 1171: 1168: 1165: 1160: 1133: 1115: 1112: 1094: 1091: 1090: 1089: 1078: 1072: 1069: 1066: 1063: 1060: 1057: 1053: 1048: 1045: 1042: 1037: 1033: 1029: 1026: 1023: 1020: 1017: 1014: 1009: 1005: 1001: 998: 995: 992: 989: 986: 983: 980: 977: 974: 971: 968: 954: 953: 942: 939: 931: 925: 919: 913: 907: 899: 891: 885: 879: 871: 863: 855: 849: 846: 843: 838: 833: 807: 804: 773: 768: 763: 745: 742: 711: 706: 701: 688:disjoint union 657: 633: 619: 616: 608: 607: 593: 590: 584: 580: 572: 568: 562: 557: 554: 551: 547: 543: 540: 537: 534: 531: 502: 498: 463: 459: 447: 446: 433: 429: 423: 419: 413: 408: 405: 402: 398: 394: 391: 388: 385: 382: 349: 332: 329: 316: 313: 310: 307: 304: 301: 298: 295: 292: 289: 269: 266: 263: 243: 240: 237: 234: 231: 228: 224: 220: 217: 214: 211: 191: 188: 185: 182: 162: 159: 156: 153: 78:twelvefold way 55: 38: 22:is an area of 15: 9: 6: 4: 3: 2: 2246: 2235: 2232: 2231: 2229: 2218: 2214: 2210: 2208:0-12-751956-4 2204: 2200: 2199: 2194: 2190: 2187: 2183: 2180: 2176: 2175:Riordan, John 2173: 2170: 2166: 2162: 2158: 2157: 2152: 2148: 2145: 2142: 2141:0-521-56069-1 2138: 2134: 2133:0-521-55309-1 2130: 2126: 2122: 2120: 2115: 2112: 2109: 2105: 2101: 2097: 2093: 2089: 2085: 2081: 2079:0-14-012529-9 2075: 2071: 2070:Penguin Books 2067: 2062: 2059: 2058:0-262-07169-X 2055: 2051: 2047: 2043: 2039: 2036: 2034: 2033: 2028: 2024: 2021: 2019: 2015: 2012: 2011: 2002: 1999: 1997: 1994: 1992: 1989: 1987: 1984: 1982: 1979: 1977: 1974: 1972: 1969: 1967: 1964: 1962: 1959: 1957: 1954: 1952: 1949: 1948: 1941: 1937: 1933: 1928: 1924: 1921:. Therefore, 1920: 1916: 1911: 1909: 1905: 1901: 1897: 1893: 1889: 1885: 1881: 1849: 1846: 1843: 1838: 1835: 1832: 1829: 1815: 1812: 1807: 1805: 1795: 1787: 1784: 1770: 1765: 1762: 1747: 1744: 1739: 1736: 1734: 1724: 1716: 1713: 1710: 1696: 1691: 1688: 1668: 1665: 1662: 1658: 1649: 1645: 1636: 1633: 1628: 1625: 1623: 1613: 1610: 1607: 1604: 1597: 1594: 1584: 1580: 1573: 1568: 1565: 1555: 1551: 1544: 1542: 1532: 1526: 1523: 1520: 1517: 1512: 1509: 1498: 1494: 1487: 1481: 1475: 1467: 1463: 1456: 1454: 1447: 1443: 1431: 1430: 1429: 1427: 1423: 1402: 1396: 1393: 1390: 1387: 1382: 1379: 1373: 1367: 1361: 1354: 1353: 1352: 1350: 1346: 1321: 1315: 1312: 1309: 1305: 1299: 1296: 1290: 1284: 1277: 1276: 1275: 1249: 1245: 1241: 1222: 1212:In this case 1175: 1169: 1163: 1149: 1148: 1147: 1121: 1111: 1108: 1104: 1100: 1076: 1067: 1061: 1058: 1055: 1051: 1046: 1043: 1040: 1035: 1024: 1018: 1012: 1007: 996: 990: 984: 978: 972: 969: 966: 959: 958: 957: 940: 937: 923: 911: 897: 883: 869: 853: 847: 844: 817: 816: 815: 813: 803: 801: 797: 793: 789: 766: 751: 741: 739: 735: 731: 727: 704: 689: 685: 681: 677: 673: 615: 613: 591: 588: 582: 578: 570: 566: 555: 552: 549: 545: 541: 535: 529: 522: 521: 520: 518: 500: 496: 487: 483: 479: 461: 457: 431: 427: 421: 417: 406: 403: 400: 396: 392: 386: 380: 373: 372: 371: 369: 365: 337: 328: 314: 308: 302: 299: 293: 287: 261: 241: 232: 226: 222: 215: 209: 186: 180: 157: 151: 143: 138: 136: 132: 128: 124: 120: 116: 112: 108: 104: 100: 99: 93: 91: 87: 83: 79: 75: 74:combinatorial 71: 67: 63: 58: 54: 50: 46: 41: 37: 33: 30:and counting 29: 25: 24:combinatorics 21: 2197: 2185: 2178: 2155: 2118: 2065: 2049: 2042:Grötschel M. 2031: 2001:Sieve theory 1935: 1931: 1926: 1922: 1914: 1912: 1902:is based on 1895: 1891: 1887: 1883: 1879: 1877: 1425: 1421: 1419: 1348: 1344: 1342: 1247: 1243: 1239: 1211: 1117: 1105:and plane), 1096: 955: 809: 799: 795: 791: 787: 747: 737: 733: 729: 725: 683: 679: 675: 671: 621: 609: 481: 477: 448: 367: 363: 334: 139: 122: 118: 114: 110: 96: 94: 86:combinations 82:permutations 61: 56: 52: 48: 39: 35: 32:permutations 28:combinations 19: 18: 1910:is needed. 1900:square root 810:A (finite) 486:coefficient 64:. Although 2217:0831.05001 2169:0486435970 2100:143984884X 2008:References 1107:Dyck paths 142:asymptotic 103:factorials 90:partitions 2153:(2004). 2092:CRC Press 1847:− 1836:− 1785:− 1740:− 1711:− 1674:∞ 1659:∑ 1629:− 1608:− 1574:− 1521:− 1513:− 1391:− 1383:− 1313:− 1223:∙ 1176:× 1170:∙ 1059:− 1044:⋯ 941:⋯ 938:∪ 924:× 912:× 898:∪ 884:× 870:∪ 854:∪ 848:ϵ 806:Sequences 767:× 705:∪ 561:∞ 546:∑ 412:∞ 397:∑ 300:∼ 268:∞ 265:→ 239:→ 113:cards is 60:for each 2228:Category 2195:(1994). 2177:(1958). 1944:See also 812:sequence 66:counting 2215:  2205:  2167:  2139:  2131:  2106:  2098:  2076:  2056:  2044:, and 1242:. Let 1120:cycles 1103:binary 935:  901:  895:  873:  867:  857:  851:  678:) and 449:where 107:powers 1099:trees 744:Pairs 618:Union 2203:ISBN 2165:ISBN 2149:and 2137:ISBN 2129:ISBN 2104:ISBN 2096:ISBN 2074:ISBN 2054:ISBN 2025:and 732:) + 646:and 121:) = 88:and 2213:Zbl 2163:. 2127:. 2102:, 2094:. 2090:. 2040:, 1890:in 1351:): 1182:Seq 827:Seq 802:). 740:). 488:of 254:as 202:if 133:or 2230:: 2211:. 2159:. 2135:, 2123:. 2072:. 2029:, 2016:, 1940:. 1938:−1 1930:= 1428:: 105:, 92:. 84:, 2219:. 2171:. 2143:. 2110:. 2082:. 2060:. 1936:n 1932:c 1927:n 1923:p 1915:n 1896:x 1894:( 1892:f 1888:x 1884:x 1882:( 1880:f 1856:) 1850:1 1844:n 1839:2 1833:n 1830:2 1824:( 1816:n 1813:1 1808:= 1796:n 1792:) 1788:4 1782:( 1776:) 1771:n 1766:2 1763:1 1756:( 1748:2 1745:1 1737:= 1725:k 1721:) 1717:x 1714:4 1708:( 1702:) 1697:k 1692:2 1689:1 1682:( 1669:0 1666:= 1663:k 1655:] 1650:n 1646:x 1642:[ 1637:2 1634:1 1626:= 1614:x 1611:4 1605:1 1598:2 1595:1 1590:] 1585:n 1581:x 1577:[ 1569:2 1566:1 1561:] 1556:n 1552:x 1548:[ 1545:= 1533:2 1527:x 1524:4 1518:1 1510:1 1504:] 1499:n 1495:x 1491:[ 1488:= 1485:) 1482:x 1479:( 1476:P 1473:] 1468:n 1464:x 1460:[ 1457:= 1448:n 1444:p 1426:x 1422:n 1403:2 1397:x 1394:4 1388:1 1380:1 1374:= 1371:) 1368:x 1365:( 1362:P 1349:x 1347:( 1345:P 1325:) 1322:x 1319:( 1316:P 1310:1 1306:1 1300:x 1297:= 1294:) 1291:x 1288:( 1285:P 1260:P 1248:x 1246:( 1244:P 1240:x 1226:} 1220:{ 1197:) 1192:P 1187:( 1173:} 1167:{ 1164:= 1159:P 1132:P 1101:( 1077:. 1071:) 1068:x 1065:( 1062:F 1056:1 1052:1 1047:= 1041:+ 1036:3 1032:] 1028:) 1025:x 1022:( 1019:F 1016:[ 1013:+ 1008:2 1004:] 1000:) 997:x 994:( 991:F 988:[ 985:+ 982:) 979:x 976:( 973:F 970:+ 967:1 930:F 918:F 906:F 890:F 878:F 862:F 845:= 842:) 837:F 832:( 800:x 798:( 796:G 794:) 792:x 790:( 788:F 772:G 762:F 738:x 736:( 734:G 730:x 728:( 726:F 710:G 700:F 684:x 682:( 680:G 676:x 674:( 672:F 656:G 632:F 592:! 589:n 583:n 579:x 571:n 567:f 556:0 553:= 550:n 542:= 539:) 536:x 533:( 530:F 501:n 497:x 482:n 478:n 462:n 458:f 432:n 428:x 422:n 418:f 407:0 404:= 401:n 393:= 390:) 387:x 384:( 381:F 368:x 366:( 364:F 348:F 315:. 312:) 309:n 306:( 303:g 297:) 294:n 291:( 288:f 262:n 242:1 236:) 233:n 230:( 227:g 223:/ 219:) 216:n 213:( 210:f 190:) 187:n 184:( 181:f 161:) 158:n 155:( 152:g 123:n 119:n 117:( 115:f 111:n 62:n 57:n 53:S 40:i 36:S

Index

combinatorics
combinations
permutations
natural numbers
counting
mathematical problem
combinatorial
twelvefold way
permutations
combinations
partitions
closed formulas
factorials
powers
algebraic enumeration
recurrence relation
generating function
asymptotic
Generating functions
coefficient
exponential generating function
differentiation
disjoint union
Cartesian product
sequence
trees
binary
Dyck paths
cycles
square root

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