OFFSET
0,3
FORMULA
a(0) = 1, a(1) = 0; a(n) = Sum_{k=2..n} k! * sigma_{k-1}(k-1)/(k-1) * binomial(n-1,k-1) * a(n-k).
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/prod(k=1, N, (1-(k*x)^k)^(1/k))^x))
(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=2, i, j!*sigma(j-1, j-1)/(j-1)*binomial(i-1, j-1)*v[i-j+1])); v;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 14 2022
STATUS
approved