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 A004421 Expansion of (Sum_{n=-inf..inf} x^(n^2))^(-20). 1
 1, -40, 840, -12320, 141640, -1358448, 11297440, -83631680, 561539400, -3468363400, 19922193200, -107343635040, 546373245600, -2642351627440, 12200693947200, -54007656632000, 230002160331080, -945228781171920 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..10000 FORMULA a(n) ~ (-1)^n * exp(Pi*sqrt(m*n)) * m^((m+1)/4) / (2^(3*(m+1)/2) * n^((m+3)/4)), set m = 20 for this sequence. - Vaclav Kotesovec, Aug 18 2015 MATHEMATICA nmax = 30; CoefficientList[Series[Product[((1 + (-x)^k)/(1 - (-x)^k))^20, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Aug 18 2015 *) nmax = 30; CoefficientList[Series[EllipticTheta[3, 0, x]^(-20), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 24 2017 *) CROSSREFS Sequence in context: A162402 A010992 A250584 * A247411 A250986 A190825 Adjacent sequences: A004418 A004419 A004420 * A004422 A004423 A004424 KEYWORD sign AUTHOR STATUS approved

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Last modified March 29 22:15 EDT 2023. Contains 361599 sequences. (Running on oeis4.)