A357088 E.g.f. satisfies A(x) * log(A(x)) = (exp(x*A(x)) - 1)^2 / 2.
1, 0, 1, 3, 16, 135, 1246, 14238, 192613, 2948025, 51071236, 985911003, 20952667660, 486857940660, 12275673296251, 333786662478363, 9737819506544272, 303399477464036175, 10054949172135522106, 353197317869395005258, 13108298181041284002769
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n\2, (2*k)!*(n-k+1)^(k-1)*stirling(n, 2*k, 2)/(2^k*k!));
Formula
a(n) = Sum_{k=0..floor(n/2)} (2*k)! * (n-k+1)^(k-1) * Stirling2(n,2*k)/(2^k * k!).