OFFSET
0,4
EXAMPLE
G.f.: A(x) = 1 + x + x^2 + 2*x^3 + 5*x^4 + 17*x^5 + 51*x^6 + 199*x^7 +...
A(x)*A(-x) = 1 + x^2 + 7*x^4 + 74*x^6 + 967*x^8 + 14251*x^10 + 227037*x^12 +...
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=1, n, A=1+sum(m=1, n, x^m*A^(m^2)*subst(A^(m^2), x, -x))); polcoeff(A, n)}
for(n=0, 21, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 21 2012
STATUS
approved