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A308304
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a(n) = (i^n)*Sum_{k=0..n} B_k*|s(n+1,k+1)|*(n+1)^k.
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0
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1, 0, 1, 0, 24, 0, 3396, 0, 1706112, 0, 2277172800, 0, 6690143635200, 0, 38006393154105600, 0, 380203596126189158400, 0, 6242084318591496668160000, 0, 159215887013285165806891008000
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OFFSET
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0,5
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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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PROG
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(PARI) a(n) = (I^n)*sum(k=0, n, bernfrac(k)*abs(stirling(n+1, k+1, 1))*(n+1)^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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