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A286483
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a(n) = (i^n)*Sum_{k=0..n} (k+1)*B_k*|s(n+2,k+2)|*(n+2)^k.
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1
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1, 0, 5, 0, 238, 0, 51508, 0, 35028576, 0, 59053389408, 0, 209726098354368, 0, 1397532391623302400, 0, 16043549794523492290560, 0, 297285345537576037788672000, 0, 8447414796960536731803240038400
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OFFSET
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0,3
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COMMENTS
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|s(n,k)| is the unsigned Stirling number of first kind (see A008275), B_k is the Bernoulli number and i^2=-1. All even-indexed terms are positive integers, and the odd-indexed terms are zero. A generating function would be welcomed.
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LINKS
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MATHEMATICA
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list = {};
nlim = 20; Do[s=(-1)^(n/2) Sum[(-1)^(n-k)*(k+1)*BernoulliB[k]*StirlingS1[n+2, k+2]*(n+2)^k, {k, 0, n}]; AppendTo[list, s], {n, 0, nlim}]; Print[list]
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PROG
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(PARI) a(n) = (I^n)*sum(k=0, n, (k+1)*bernfrac(k)*abs(stirling(n+2, k+2, 1))*(n+2)^k); \\ Michel Marcus, May 19 2019
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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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