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A305206
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a(n) = [x^n] exp(Sum_{k>=1} (-1)^(k+1)*x^k/(k*(1 - x^k)^n)).
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8
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1, 1, 2, 9, 36, 190, 1070, 6797, 46942, 350901, 2806187, 23894662, 215598410, 2053090936, 20557071012, 215697357449, 2364810631734, 27023086395647, 321160376470277, 3962047673946906, 50648323260067319, 669819485900273336, 9150740338219903590, 128965789655207156299
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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) = [x^n] Product_{k>=1} (1 + x^k)^binomial(n+k-2,n-1).
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MATHEMATICA
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Table[SeriesCoefficient[Exp[Sum[(-1)^(k + 1) x^k/(k (1 - x^k)^n), {k, 1, n}]], {x, 0, n}], {n, 0, 23}]
Table[SeriesCoefficient[Product[(1 + x^k)^Binomial[n + k - 2, n - 1], {k, 1, n}], {x, 0, n}], {n, 0, 23}]
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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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