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A022615
Expansion of Product_{m>=1} (1+q^m)^(-20).
2
1, -20, 190, -1160, 5245, -19324, 62150, -182040, 495750, -1269620, 3088376, -7197240, 16164595, -35136760, 74192590, -152674048, 306968470, -604298520, 1166898210, -2213813640, 4132159452, -7597272900
OFFSET
0,2
LINKS
FORMULA
a(n) ~ (-1)^n * 5^(1/4) * exp(Pi*sqrt(10*n/3)) / (2 * 6^(1/4) * n^(3/4)). - Vaclav Kotesovec, Aug 27 2015
a(0) = 1, a(n) = -(20/n)*Sum_{k=1..n} A000593(k)*a(n-k) for n > 0. - Seiichi Manyama, Apr 05 2017
MATHEMATICA
nmax = 50; CoefficientList[Series[Product[1/(1 + x^k)^20, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Aug 27 2015 *)
CROSSREFS
Sequence in context: A047645 A010936 A014806 * A171075 A061180 A125383
KEYWORD
sign
STATUS
approved