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A356688
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a(n) = n! * Sum_{k=0..n} k^(3*n)/k!.
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3
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1, 1, 66, 21225, 18952156, 36175231585, 126556309395486, 733064060959310689, 6540867625730306094360, 85180334386943946887707617, 1552697061493449955344530003290, 38315904135534199560725372265381721, 1245605749857294018587318829355458646068
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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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E.g.f.: Sum_{k>=0} (k^3 * x)^k / (k! * (1 - k^3 * x)).
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MATHEMATICA
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a[n_] := n! * Sum[k^(3*n)/k!, {k, 0, n}]; a[0] = 1; Array[a, 13, 0] (* Amiram Eldar, Aug 23 2022 *)
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PROG
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(PARI) a(n) = n!*sum(k=0, n, k^(3*n)/k!);
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (k^3*x)^k/(k!*(1-k^3*x)))))
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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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