OFFSET
0,3
COMMENTS
a(n) is divisible by n for n>0.
FORMULA
The g.f. of A120957 equals B(x) = x/series_reversion(x*A(x)), so that both A(x) = B(x*A(x)) and B(x) = A(x/B(x)) equivalently hold.
PROG
(PARI) {a(n)=my(A=[1, 1]); if(n==0||n==1, 1, for(i=1, n, A=concat(A, 0); A[ #A]=(#A-2)*Vec(serreverse(x/Ser(A)))[ #A]); A[n+1]*n/(n-1))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 21 2006
STATUS
approved