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A297322
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a(n) = [x^n] Product_{k>=1} (1 + k*x^k)^n.
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7
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1, 1, 5, 28, 137, 726, 3896, 21071, 115089, 633007, 3500740, 19448573, 108458924, 606787572, 3404112479, 19142919543, 107874784017, 609021410570, 3443952349385, 19503777943838, 110599636109572, 627924447630011, 3568885868192419, 20304321490356084
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) ~ c * d^n / sqrt(n), where d = 5.814548482877687529318372516965305077397562... and c = 0.2563102401728134539247148322678842806264... - Vaclav Kotesovec, Aug 01 2019
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MAPLE
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f:= proc(n) local k;
coeff(series(mul((1+k*x^k)^n, k=1..n), x, n+1), x, n);
end proc:
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MATHEMATICA
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Table[SeriesCoefficient[Product[(1 + k x^k)^n, {k, 1, n}], {x, 0, n}], {n, 0, 24}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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