OFFSET
1,3
EXAMPLE
G.f.: A(x) = x + x^2 - 2*x^3 + 10*x^4 - 62*x^5 + 466*x^6 - 4004*x^7 +-...
A(A(x)) = x + 2*x^2 - 2*x^3 + 11*x^4 - 62*x^5 + 464*x^6 - 4004*x^7 +-...
PROG
(PARI) {a(n)=local(A=x+x^2); for(i=0, n, A=x+subst(A, x, serreverse(A+x*O(x^n))^2)); polcoeff(A, n)}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Jun 10 2008
STATUS
approved