OFFSET
0,3
PROG
(PARI) {a(n)=sum(k=0, n\2, 2^k*(n\2)!*((n+1)\2)!*polcoeff(polcoeff(exp((1+y)*(exp(x+x*O(x^n))-1)), n\2), k) *polcoeff(polcoeff(exp((1+y)*(exp(x+x*O(x^n))-1)), (n+1)\2), k))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 08 2006
STATUS
approved