A277510 E.g.f.: -1/(1-LambertW(-x))^2.

-1, 2, -2, 6, 8, 170, 1872, 29246, 519808, 10698642, 248787200, 6458737142, 185138721792, 5808233422394, 197952647108608, 7283047491096750, 287705410381709312, 12145740050403520034, 545696709922799419392, 25998534614835587104742, 1309210567403228200960000

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. A063170, A134095, A277458, A277490, A308506.

Programs

Mathematica

CoefficientList[Series[-1/(1-LambertW[-x])^2, {x, 0, 20}], x] * Range[0, 20]!

PARI

x='x+O('x^50); Vec(serlaplace(-1/(1 - lambertw(-x))^2)) \\ G. C. Greubel, Nov 08 2017

Formula

a(n) ~ n^(n-1) / 4.