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A370604
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a(n) = n! * Sum_{d|n} 1/((d-1)! * (n/d)^d).
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0
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1, 3, 5, 16, 29, 251, 727, 7988, 47049, 512767, 3628811, 58012582, 479001613, 8007115559, 92633212687, 1648230784216, 20922789888017, 449622885136443, 6402373705728019, 146721895942876274, 2507411046373376021, 60380204535989936347, 1124000727777607680023
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OFFSET
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1,2
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LINKS
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FORMULA
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If p is prime, a(p) = p + (p-1)!.
E.g.f.: Sum_{k>0} x^k/k * exp(x^k/k).
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PROG
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(PARI) a(n) = n!*sumdiv(n, d, 1/((d-1)!*(n/d)^d));
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(sum(k=1, N, x^k/k*exp(x^k/k))))
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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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