OFFSET
2,3
EXAMPLE
G.f.: A(x) = x^2 + x^3 + 2*x^4 + 3*x^5 + 7*x^6 + 14*x^7 + 36*x^8 + 85*x^9 +...
where
A(A(x)) = x^4 + 2*x^5 + 6*x^6 + 13*x^7 + 35*x^8 + 84*x^9 + 225*x^10 +...
PROG
(PARI) {a(n)=local(A=x^2+x^3); for(i=1, n, A=x^2/(1-x+x*O(x^n))+subst(A, x, A+x*O(x^n))); polcoeff(A, n)}
for(n=2, 40, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 24 2012
STATUS
approved