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A293848
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E.g.f.: exp(Sum_{n>=1} n^n*x^n).
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2
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1, 1, 9, 187, 7033, 421341, 37025881, 4500154639, 723834652017, 148905928574713, 38133707320119241, 11894979981772431171, 4439223538343665367209, 1952818695816854110909717, 999887879061130705615605273, 589500991222520435444933020951
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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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a(0) = 1 and a(n) = (n-1)! * Sum_{k=1..n} k^(k+1)*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*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*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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