A383260 Expansion of e.g.f. f(x) * exp(f(x)), where f(x) = (exp(3*x) - 1)/3.
0, 1, 5, 30, 211, 1691, 15126, 148975, 1599401, 18563832, 231317677, 3076301471, 43448641176, 648950825173, 10212710942609, 168797691270438, 2921824286030527, 52833169082034839, 995732022426733782, 19519908917429511307, 397294691005861642805, 8381466690394292755896
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=1, n, k*3^(n-k)*stirling(n, k, 2));
Formula
a(n) = Sum_{k=1..n} k * 3^(n-k) * Stirling2(n,k).