A360886 - OEIS

A360886

G.f. satisfies A(x) = 1 + x * A(x * (1 + x^3)).

1, 1, 1, 1, 1, 2, 4, 7, 11, 22, 49, 104, 212, 471, 1112, 2584, 6000, 14574, 36488, 91148, 230011, 596893, 1574433, 4171388, 11193376, 30594229, 84527225, 235243027, 662702701, 1891111335, 5443353369, 15797764276, 46336647188, 137245713050, 409670144432

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OFFSET

0,6

LINKS

Table of n, a(n) for n=0..34.

FORMULA

a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/4)} binomial(n-1-3*k,k) * a(n-1-3*k).

PROG

(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\4, binomial(i-1-3*j, j)*v[i-3*j])); v;

CROSSREFS

Cf. A127782, A360885.

Cf. A360897.