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A022615 Expansion of Product_{m>=1} (1+q^m)^(-20). 2

%I #13 Apr 05 2017 11:26:15

%S 1,-20,190,-1160,5245,-19324,62150,-182040,495750,-1269620,3088376,

%T -7197240,16164595,-35136760,74192590,-152674048,306968470,-604298520,

%U 1166898210,-2213813640,4132159452,-7597272900

%N Expansion of Product_{m>=1} (1+q^m)^(-20).

%H Seiichi Manyama, <a href="/A022615/b022615.txt">Table of n, a(n) for n = 0..10000</a>

%F 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

%F a(0) = 1, a(n) = -(20/n)*Sum_{k=1..n} A000593(k)*a(n-k) for n > 0. - _Seiichi Manyama_, Apr 05 2017

%t nmax = 50; CoefficientList[Series[Product[1/(1 + x^k)^20, {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Aug 27 2015 *)

%K sign

%O 0,2

%A _N. J. A. Sloane_

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Last modified April 23 08:19 EDT 2024. Contains 371905 sequences. (Running on oeis4.)