A171209 G.f. satisfies: A(x) = (1 + x*A(2x))^7.

1, 7, 119, 3955, 247093, 29355725, 6770018269, 3075928905505, 2774997766597238, 4989660046676105752, 17913062958150482828608, 128508635121001835101510976, 1843071985575998120371392747776, 52855626540938653363337299348546560, 3031270298538159379928340759759663584000

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Formula

Self-convolution 7th power of A171208 where a(n) = A171208(n+1)/2^n for n>=0.

Mathematica

terms = 15; A[_] = 0; Do[A[x_] = (1+x*A[2x])^7 + O[x]^terms // Normal, terms]; CoefficientList[A[x], x] (* Stefano Spezia, Apr 02 2025 *)

Prog

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n, A=(1+x*subst(A, x, 2*x))^7); polcoeff(A, n)}

Crossrefs

Cf. A135868, A171200-A171207, A171208, A171210-A171211.

Sequence in context: A357351 A376040 A192565 * A296731 A092612 A263943

Adjacent sequences: A171206 A171207 A171208 * A171210 A171211 A171212

Keyword

nonn

Author

Paul D. Hanna, Dec 05 2009

Extensions

a(13)-a(14) from Stefano Spezia, Apr 02 2025

Status

approved