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.
a(n) ~ n! * (1 + 1/n^5 + 10/n^6 + 65/n^7 + 350/n^8 + 1701/n^9 + 7771/n^10 + 34150/n^11 + 146905/n^12 + ...), the coefficients are Sum_{j=0..(k-4)/5} Stirling2(k,5*j+4). - Vaclav Kotesovec, Nov 24 2022
PROG
(PARI) a(n) = sum(k=0, n\5, (n-5*k)!);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Nov 19 2022
STATUS
approved