A368440 Expansion of e.g.f. exp(x) / (3 - 2*exp(3*x)).

1, 7, 103, 2287, 67687, 2504047, 111163303, 5757411247, 340788559207, 22693176094447, 1679047763217703, 136654363293340207, 12133120656211741927, 1167034341869994747247, 120886955198779063694503, 13416476227330202250197167, 1588276885073067052758303847

Offset

0,2

Links

Table of n, a(n) for n=0..16.

Formula

a(n) = 1 + 2 * Sum_{k=1..n} 3^k * binomial(n,k) * a(n-k).

Prog

(PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+2*sum(j=1, i, 3^j*binomial(i, j)*v[i-j+1])); v;

Crossrefs

Cf. A151919, A368441, A368453.

Sequence in context: A246914 A274670 A188946 * A365014 A234292 A357347

Adjacent sequences: A368437 A368438 A368439 * A368441 A368442 A368443

Keyword

nonn

Author

Seiichi Manyama, Dec 24 2023

Status

approved