OFFSET
0,3
PROG
(PARI) {a(n)=local(A); if(n==0, n+1, A=(n+1)*x+x*O(x^n); for(k=0, n, A+=polcoeff(A, k)*x^k*(n+1-prod(i=0, k, 1+(i-n-1)*x))); polcoeff(A, n)/(n+1)^2)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 07 2005
STATUS
approved