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Search: id:A002040
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| A002040 |
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Related to partitions.
(Formerly M1159 N0442)
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+0
2
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| 1, 2, 4, 8, 21, 52, 131, 316, 765, 1846, 4494, 10944, 26654, 64798, 157502, 382868, 931028, 2264106, 5505777, 13387880, 32553601, 79156974, 192479838, 468039888, 1138098210, 2767421826, 6729311459, 16363118556, 39788886610, 96751470494
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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J. M. Gandhi, On numbers related to partitions of a number, Amer. Math. Monthly, 76 (1969), 1033-1036.
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LINKS
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Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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FORMULA
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G.f.: 1/(f(q)') where f(-q)=Product_{k>0} (1-q^k) is one of Ramanujan's theta functions. - Michael Somos, Apr 08 2003
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PROGRAM
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(PARI) a(n)=polcoeff(1/eta(-x+x^2*O(x^n))', n)
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CROSSREFS
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Cf. A002039, A000203.
Sequence in context: A112278 A059731 A001315 this_sequence A108071 A055876 A065847
Adjacent sequences: A002037 A002038 A002039 this_sequence A002041 A002042 A002043
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas
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EXTENSIONS
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Formula corrected and sequence extended by Michael Somos
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