A293532 E.g.f.: exp(x/(x^2 - 1)).

1, -1, 1, -7, 25, -181, 1201, -10291, 97777, -1013545, 12202561, -151573951, 2173233481, -31758579997, 524057015665, -8838296029291, 164416415570401, -3145357419120721, 65057767274601217, -1391243470549894135, 31671795881695430521, -747996624368605997701

Offset: 0

Author

Seiichi Manyama, Oct 11 2017

Keywords

• sign

Crossrefs

Column k=2 of A293530.

Cf. A088009.

Programs

Mathematica

CoefficientList[Series[E^(x/(x^2 - 1)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Oct 12 2017 *)

PARI

N=66; x='x+O('x^N); Vec(serlaplace(exp(x/(x^2-1))))

Formula

E.g.f.: Product_{k>=1} 1/(1 + x^k)^(phi(k)/k), where phi() is the Euler totient function (A000010). - Ilya Gutkovskiy, May 25 2019