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A292416
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a(n) = [x^n] Product_{k>=1} (1 + 2^n*x^k) / (1 - 2^n*x^k).
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3
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1, 4, 40, 1296, 149024, 71573568, 141871849600, 1143771307901184, 37183988027710374400, 4854666820584582571623424, 2540262650941956832151944038400, 5322109355556594174041950822678401024, 44623279107562668799968801377926722975965184
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n) ~ 2^(n^2 + 1).
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MATHEMATICA
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nmax = 15; Table[SeriesCoefficient[Product[(1+2^n*x^k)/(1-2^n*x^k), {k, 1, n}], {x, 0, n}], {n, 0, nmax}]
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PROG
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(PARI) {a(n)= polcoef(prod(k=1, n, ((1+2^n*x^k)/(1-2^n*x^k) +x*O(x^n))), n)};
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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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