OFFSET
0,7
FORMULA
a(0) = 1; a(n) = (n-1)! * Sum_{k=0..floor((n-1)/5)} a(n-5*k-1)/(n-5*k-1)!.
a(0) = a(1) = ... = a(4) = 1; a(n) = a(n-1) + 120 * binomial(n-1,5) * a(n-5).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=0, N\5, x^(5*k+1)/(5*k+1)))))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 23 2023
STATUS
approved