VOOZH about

URL: https://oeis.org/A385607

⇱ A385607 - OEIS

login
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, 1, 121, 721, 115921, 1254121, 175667521, 2723150641, 328524651841, 6553910658241, 694593264839761, 16751100559753561, 1592929589394223081, 44555491032952142881, 3872288533662063462481, 121957120480085202781681, 9836937778718128127534881, 341177468192261294809070401
OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..floor(n/2)} (n+3*k)!/(k!^5 * (n-2*k)!).
PROG
(PARI) a(n) = sum(k=0, n\2, (n+3*k)!/(k!^5*(n-2*k)!));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 04 2025
STATUS
approved