A141140 G.f. satisfies: A(A(x)) = A(x) + A(x^2).

1, 1, -2, 10, -62, 466, -4004, 37774, -383042, 4120768, -46601144, 550296628, -6751738736, 85742962300, -1123702072256, 15161509999324, -210202294372118, 2989858353554554, -43572404751879032, 649889656256427742, -9911173481433673436

Offset

1,3

Links

Table of n, a(n) for n=1..21.

Example

G.f.: A(x) = x + x^2 - 2*x^3 + 10*x^4 - 62*x^5 + 466*x^6 - 4004*x^7 +-...
A(A(x)) = x + 2*x^2 - 2*x^3 + 11*x^4 - 62*x^5 + 464*x^6 - 4004*x^7 +-...

Prog

(PARI) {a(n)=local(A=x+x^2); for(i=0, n, A=x+subst(A, x, serreverse(A+x*O(x^n))^2)); polcoeff(A, n)}

Crossrefs

Sequence in context: A175939 A192942 A307364 * A232472 A361829 A361494

Adjacent sequences: A141137 A141138 A141139 * A141141 A141142 A141143

Keyword

sign

Author

Paul D. Hanna, Jun 10 2008

Status

approved