A120957 - OEIS

%I #3 Mar 30 2012 18:36:58

%S 1,1,1,8,123,3024,106850,5110440,317955435,24986363648,2422868732514,

%T 284385893015080,39758967921029830,6530586385172586528,

%U 1245479442254732687652,272988926352496428778928

%N Sequence uniquely defined by: n*a(n) = (n-1)*[x^n] B(x) for n>1 with a(0)=a(1)=1, or, equivalently, x*A'(x) = 1+x - B(x) + x*B'(x), where B(x) = series_reversion(x/A(x))/x.

%C a(n) is divisible by (n-1) for n>1.

%F The g.f. of A120958 equals B(x) = series_reversion(x/A(x))/x, so that both A(x) = B(x/A(x)) and B(x) = A(x*B(x)) equivalently hold.

%o (PARI) {a(n)=local(A=[1,1]);for(i=1,n, A=concat(A,0);A[ #A]=(#A-2)*Vec(serreverse(x/Ser(A)))[ #A]);A[n+1]}

%K nonn

%O 0,4

%A _Paul D. Hanna_, Jul 21 2006