A304877 G.f.: Sum_{k>=0} q(k)^2 * x^k / Sum_{k>=0} q(k)*x^k, where q(n) is A000009(n).
1, 0, 0, 2, 0, 4, 4, 8, 4, 20, 20, 28, 38, 52, 80, 128, 128, 176, 300, 316, 476, 648, 832, 972, 1428, 1720, 2340, 3014, 3844, 4588, 6556, 7476, 9760, 12588, 15596, 19480, 25140, 29796, 37728, 47604, 58140, 70856, 90148, 107692, 133228, 167284, 198692, 242728
Offset: 0
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..10000
Programs
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Mathematica
nmax = 50; CoefficientList[Series[Sum[PartitionsQ[k]^2*x^k, {k, 0, nmax}] / Sum[PartitionsQ[k]*x^k, {k, 0, nmax}], {x, 0, nmax}], x]
Formula
a(n) ~ sqrt(3) * exp(Pi*sqrt(n)) / (2^(11/2) * n^(3/2)).