A365736 G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^5*A(x)^4).

1, 1, 1, 1, 1, 1, 2, 7, 22, 57, 127, 254, 478, 903, 1838, 4148, 10012, 24417, 58019, 132919, 295699, 649742, 1437719, 3247500, 7504925, 17607055, 41465646, 97197400, 226053017, 522505492, 1205674911, 2790322418, 6495170018, 15209566913, 35761582618

Offset: 0

Author

Seiichi Manyama, Sep 17 2023

Keywords

• nonn

Crossrefs

Cf. A212364, A212385, A365734, A365735.

Cf. A365701.

Programs

PARI

a(n) = sum(k=0, n\5, binomial(n-4*k-1, k)*binomial(n-k+1, n-5*k)/(n-k+1));

Formula

a(n) = Sum_{k=0..floor(n/5)} binomial(n-4*k-1,k) * binomial(n-k+1,n-5*k) / (n-k+1).