OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..449
FORMULA
a(n) = n * a(n-1) - a(n-5) + n * a(n-6) for n > 5.
PROG
(PARI) a(n) = sum(k=0, n\5, (-1)^k*(n-5*k)!);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 23 2022
STATUS
approved