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A293849
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Expansion of e.g.f.: exp(Sum_{n>=1} n^(n-1)*x^n).
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2
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1, 1, 5, 67, 1825, 85661, 6208861, 643969495, 90484635137, 16538699920825, 3811890603086101, 1081079416534448651, 369888779067183276385, 150214056908992952336917, 71424576855634502660684525, 39304140073887410352909383071
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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.: exp(Sum_{n>=1} n^(n-1)*x^n).
a(0) = 1 and a(n) = (n-1)! * Sum_{k=1..n} k^k*a(n-k)/(n-k)! for n > 0.
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MATHEMATICA
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nmax = 20; CoefficientList[Series[E^Sum[k^(k-1)*x^k, {k, 1, nmax}], {x, 0, nmax}], x] * Range[0, nmax]! (* Vaclav Kotesovec, Oct 18 2017 *)
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PROG
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(PARI) {a(n) = n!*polcoeff(exp(sum(k=1, n, k^(k-1)*x^k)+x*O(x^n)), n)}
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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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