A385607 Diagonal of the rational function 1/(1 - (v^2 + w^2 + x^2 + y^2 + z^2 + v*w*x*y*z)).

1, 1, 121, 721, 115921, 1254121, 175667521, 2723150641, 328524651841, 6553910658241, 694593264839761, 16751100559753561, 1592929589394223081, 44555491032952142881, 3872288533662063462481, 121957120480085202781681, 9836937778718128127534881, 341177468192261294809070401

Offset: 0

Author

Seiichi Manyama, Jul 04 2025

Keywords

• nonn

Crossrefs

Cf. A082489, A361636, A361703, A385606.

Programs

PARI

a(n) = sum(k=0, n\2, (n+3*k)!/(k!^5*(n-2*k)!));

Formula

a(n) = Sum_{k=0..floor(n/2)} (n+3*k)!/(k!^5 * (n-2*k)!).