%I
%S 1,1,0,2,4,6,74,190,1128,14336,51616,404856,7330520,41023048,
%T 250083744,7532037344,65189204416,185746926720,13324842809792,
%U 175157684686144,215786634724224,35458746254274944,711274631768613760
%N E.g.f. exp(tanh(log(1+x))).
%F a(n)=sum(m=1..n, sum(r=0..nm, stirling1(n,r+m)*sum(k=0..r, binomial(k+m1,m1)*(k+m)!*(1)^(k)*2^(rk)*stirling2(r+m,k+m)))/m!), n>0, a(0)=1. [From Vladimir Kruchinin, Jun 06 2011]
%t Exp[ Tanh[ Log[ 1+x ] ] ]
%o (Maxima)
%o a(n):=sum(sum(stirling1(n,r+m)*sum(binomial(k+m1,m1)*(k+m)!*(1)^(k)*2^(rk)*stirling2(r+m,k+m),k,0,r),r,0,nm)/m!,m,1,n); [From Vladimir Kruchinin, Jun 06 2011]
%K sign,easy
%O 0,4
%A _R. H. Hardin_
%E Extended with signs Mar 15 1997 by _Olivier GĂ©rard_.
