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A360193
a(n) = Sum_{k=0..n} (k-1)^(k-1) * binomial(n,k).
6
-1, 0, 2, 9, 52, 445, 5166, 75019, 1300776, 26167257, 598577770, 15337224991, 435020120316, 13529095809541, 457727913937854, 16736043791509995, 657590281425958096, 27631245762003186865, 1236355641557737359570, 58689534518861119967287
OFFSET
0,3
LINKS
Eric Weisstein's World of Mathematics, Lambert W-Function.
FORMULA
E.g.f.: -exp(x + LambertW(-x)).
E.g.f.: x * exp(x) / LambertW(-x).
a(n) ~ exp(exp(-1)-1) * n^(n-1). - Vaclav Kotesovec, Mar 06 2023
PROG
(PARI) a(n) = sum(k=0, n, (k-1)^(k-1)*binomial(n, k));
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(-exp(x+lambertw(-x))))
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(x*exp(x)/lambertw(-x)))
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Seiichi Manyama, Mar 05 2023
STATUS
approved