A127784 G.f. satisfies: A(x) = 1 + (x+x^2)*A(x+x^2)^2.
1, 1, 3, 11, 51, 266, 1540, 9681, 65291, 468401, 3551693, 28327029, 236731183, 2066583601, 18796448581, 177735656083, 1743920667437, 17725856560839, 186366309301259, 2024042644283702, 22679125592930412, 261873356070694571
Offset: 0
Keywords
Links
- Vaclav Kotesovec, Table of n, a(n) for n = 0..310
Programs
-
PARI
{a(n)=local(A=1+x+x*O(x^n));for(i=0,n,A=1+subst(x*A^2,x,x+x^2));polcoeff(A,n)}