OFFSET
0,4
FORMULA
a(0) = 1; a(n) = (n-1)! * Sum_{k=1..n} mu(k) * a(n-k)/(n-k)!.
MATHEMATICA
a[0] = 1; a[n_] := a[n] = (n - 1)! * Sum[MoebiusMu[k] * a[n - k]/(n - k)!, {k, 1, n}]; Array[a, 23, 0] (* Amiram Eldar, Apr 30 2022 *)
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N, moebius(k)*x^k/k))))
(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=(i-1)!*sum(j=1, i, moebius(j)*v[i-j+1]/(i-j)!)); v;
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Apr 29 2022
STATUS
approved