OFFSET
0,3
EXAMPLE
G.f.: A(x) = x + x^2 + 2*x^3 + 8*x^4 + 48*x^5 + 382*x^6 + 3756*x^7 +...
Related expansions:
A'(x) = 1 + 2*x + 6*x^2 + 32*x^3 + 240*x^4 + 2292*x^5 + 26292*x^6 +...
A(A(x)) = x + 2*x^2 + 6*x^3 + 27*x^4 + 166*x^5 + 1306*x^6 + 12556*x^7 +...
PROG
(PARI) {a(n)=local(A=x+x^2+x*O(x^n)); for(i=1, n, A=x+x^2*subst(A', x, A)); polcoeff(A, n)}
for(n=1, 21, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Apr 21 2012
STATUS
approved