A277508 E.g.f.: -1/((1-LambertW(-x))*(1+x)).

-1, 2, -4, 15, -44, 385, -294, 32473, 280120, 8528049, 170757910, 4748977321, 132530188308, 4210910824393, 142940443542274, 5273270156096265, 208276214340505456, 8800344095155520353, 395536292522024420142, 18853858817276143333321, 949787282108877829653580

Offset: 0

Author

Vaclav Kotesovec, Oct 18 2016

Keywords

• sign

Links

• G. C. Greubel, Table of n, a(n) for n = 0..385

Crossrefs

Cf. A277507, A277509.

Programs

Mathematica

CoefficientList[Series[-1/(1-LambertW[-x])/(1+x), {x, 0, 20}], x] * Range[0, 20]!

PARI

x='x+O('x^50); Vec(serlaplace(-1/((1 - lambertw(-x))*(1+x)))) \\ G. C. Greubel, Nov 08 2017

Formula

a(n) ~ n^(n-1) / (4*(1+exp(-1))).