A365697 G.f. satisfies A(x) = 1 + x^4*A(x)^3 / (1 - x*A(x)).

1, 0, 0, 0, 1, 1, 1, 1, 4, 8, 13, 19, 38, 79, 153, 273, 509, 999, 1979, 3818, 7331, 14279, 28189, 55599, 109275, 215165, 426093, 846638, 1683215, 3348212, 6673679, 13333171, 26679522, 53437369, 107151335, 215154204, 432586412, 870678377, 1754094266

Offset

0,9

Links

Table of n, a(n) for n=0..38.

Formula

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

Prog

(PARI) a(n) = sum(k=0, n\4, binomial(n-3*k-1, n-4*k)*binomial(n-k+1, k)/(n-k+1));

Crossrefs

Cf. A023427, A215341, A215342, A357308, A365696.

Cf. A365245.

Sequence in context: A064609 A327566 A307159 * A312212 A312213 A312214

Adjacent sequences: A365694 A365695 A365696 * A365698 A365699 A365700

Keyword

nonn

Author

Seiichi Manyama, Sep 16 2023

Status

approved