OFFSET
0,2
FORMULA
G.f.: A(x) = (1/x)*G(x)/(1 - G(x)) where G(x) = x + x*G(G(x)) is g.f. of A030266.
EXAMPLE
A(x) = 1 + 2*x + 5*x^2 + 15*x^3 + 53*x^4 + 217*x^5 + 1011*x^6 +...
where 1 - 1/(1 + x*A(x)) = G(x) is the g.f. of A030266:
G(x) = x + x^2 + 2*x^3 + 6*x^4 + 23*x^5 + 104*x^6 + 531*x^7 + 2982*x^8+..
PROG
(PARI) {a(n)=local(G=x+x^2); for(i=0, n, G=x+x*subst(G, x, G+x^2*O(x^n))); polcoeff((-1+1/(1-G))/x, n, x)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 26 2006
STATUS
approved