A377324 E.g.f. satisfies A(x) = 1 + (exp(x*A(x)^3) - 1)/A(x).
1, 1, 5, 52, 839, 18436, 513797, 17366224, 690366875, 31565619916, 1632064968929, 94159057903384, 5996889060457055, 417920884113926740, 31634205840603000221, 2584579552124805784672, 226699825143636127509347, 21247444370267806167804316, 2119206766514801966851437113
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, (3*n-k)!/(3*n-2*k+1)!*stirling(n, k, 2));
Formula
a(n) = Sum_{k=0..n} (3*n-k)!/(3*n-2*k+1)! * Stirling2(n,k).