OFFSET
0,2
COMMENTS
Column 3 of triangle A215241.
EXAMPLE
G.f.: 1 = 1/(1+x)^9 + 9*x/(1+x)^16 + 99*x^2/(1+x)^25 + 1416*x^3/(1+x)^36 + 25650*x^4/(1+x)^49 +...
PROG
(PARI) {a(n)=if(n==0, 1, polcoeff(1-sum(k=0, n-1, a(k)*x^k/(1+x+x*O(x^n))^((k+3)^2)), n))}
for(n=0, 21, print1(a(n)", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 06 2012
STATUS
approved