OFFSET
0,4
FORMULA
a(n) = Sum_{k=1..n} (n-k)^(k-1) * |Stirling1(n,k)|.
E.g.f.: Series_Reversion( exp(-x) * (1 - exp(-x * exp(x))) ). - Seiichi Manyama, Sep 09 2024
PROG
(PARI) a(n) = sum(k=1, n, (n-k)^(k-1)*abs(stirling(n, k, 1)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 27 2022
STATUS
approved