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

0,3

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..310

Prog

(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)}

Crossrefs

Cf. A127782, A127783.

Sequence in context: A199212 A113283 A326519 * A112696 A346967 A192925

Adjacent sequences: A127781 A127782 A127783 * A127785 A127786 A127787

Keyword

nonn

Author

Paul D. Hanna, Jan 28 2007

Status

approved