A365735 G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^5*A(x)^3).

1, 1, 1, 1, 1, 1, 2, 6, 16, 36, 71, 128, 223, 403, 796, 1706, 3775, 8252, 17485, 35986, 72988, 148594, 307833, 650947, 1395846, 3004732, 6443836, 13732127, 29134320, 61792707, 131525272, 281463507, 605273669, 1305373379, 2817407854, 6077804871, 13103021422

Offset: 0

Author

Seiichi Manyama, Sep 17 2023

Keywords

• nonn

Crossrefs

Cf. A212364, A212385, A365734, A365736.

Cf. A365733, A365700.

Programs

PARI

a(n) = sum(k=0, n\5, binomial(n-4*k-1, k)*binomial(n-2*k+1, n-5*k)/(n-2*k+1));

Formula

a(n) = Sum_{k=0..floor(n/5)} binomial(n-4*k-1,k) * binomial(n-2*k+1,n-5*k) / (n-2*k+1).