login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

E.g.f.: -exp(x)*LambertW(-x).
19

%I #13 Jul 17 2022 23:30:56

%S 0,1,4,18,116,1060,12702,187810,3296120,66897288,1540762010,

%T 39693752494,1130866726596,35300006582620,1198036854980630,

%U 43921652697277170,1729775120233353968,72831210167041246480,3264674481128340280242,155220967397580333229270

%N E.g.f.: -exp(x)*LambertW(-x).

%H G. C. Greubel, <a href="/A277473/b277473.txt">Table of n, a(n) for n = 0..385</a>

%F a(n) = Sum_{k=1..n} binomial(n,k) * k^(k-1).

%F a(n) ~ exp(exp(-1)) * n^(n-1).

%t CoefficientList[Series[-Exp[x]*LambertW[-x], {x, 0, 20}], x] * Range[0, 20]!

%t Table[Sum[Binomial[n, k]*k^(k-1), {k, 1, n}], {n, 0, 20}]

%o (PARI) x='x+O('x^50); concat([0], Vec(serlaplace(-exp(x)*lambertw(-x)))) \\ _G. C. Greubel_, Jun 11 2017

%Y Cf. A000169, A069856, A086331, A277474.

%Y Partial sums of A038051.

%K nonn

%O 0,3

%A _Vaclav Kotesovec_, Oct 17 2016