OFFSET
1,2
LINKS
Vaclav Kotesovec, Graph - the asymptotic ratio (10000 terms)
FORMULA
a(n) = n! * Sum_{k=1..n} A055225(k)/k.
E.g.f.: -(1/(1-x)) * Sum_{k>0} log(1 - k*x^k)/k.
a(n) ~ (n-1)! * 3^((n + 3 - mod(n,3))/3)/2. - Vaclav Kotesovec, Aug 07 2022
PROG
(PARI) a(n) = n!*sum(k=1, n, sumdiv(k, d, d^(k/d))/k);
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(-sum(k=1, N, log(1-k*x^k)/k)/(1-x)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 07 2022
STATUS
approved