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A022604
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Expansion of Product_{m>=1} (1+q^m)^(-9).
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4
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1, -9, 36, -93, 207, -459, 957, -1827, 3357, -6061, 10620, -18045, 30006, -49122, 79128, -125247, 195435, -301599, 460167, -694026, 1036368, -1534305, 2252277, -3278709, 4736973, -6797196, 9689103, -13722487
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) ~ (-1)^n * 3^(1/4) * exp(Pi*sqrt(3*n/2)) / (2^(7/4) * n^(3/4)). - Vaclav Kotesovec, Aug 27 2015
G.f.: exp(-9*Sum_{k>=1} (-1)^(k+1)*x^k/(k*(1 - x^k))). - Ilya Gutkovskiy, Feb 06 2018
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MATHEMATICA
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nmax = 50; CoefficientList[Series[Product[1/(1 + x^k)^9, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Aug 27 2015 *)
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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