A009439 Expansion of e.g.f. log(1+x)/exp(tanh(x)).

0, 1, -3, 8, -16, 29, -191, 1980, -14456, 85713, -657171, 7877880, -97759608, 1100545341, -13021637695, 185198054748, -2933940050000, 46990261427073, -774002505048195, 13811029423532424, -266175983849182016

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..448

Mathematica

With[{nn=20}, CoefficientList[Series[Log[1+x]/Exp[Tanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, May 19 2023 *)

Prog

(Magma)
R<x>:=PowerSeriesRing(Rationals(), 30);
[0] cat Coefficients(R!(Laplace( Log(1+x)*Exp(-Tanh(x)) ))); // G. C. Greubel, Sep 08 2023
(SageMath)
def A009439_list(prec):
    P.<x> = PowerSeriesRing(QQ, prec)
    return P( log(1+x)*exp(-tanh(x)) ).egf_to_ogf().list()
A009439_list(31) # G. C. Greubel, Sep 08 2023

Crossrefs

Cf. A009405 - A009420, A009422 - A009438.

Sequence in context: A009858 A169947 A167616 * A000233 A002624 A293358

Adjacent sequences: A009436 A009437 A009438 * A009440 A009441 A009442

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified and previous Mathematica program replaced by Harvey P. Dale, May 19 2023

Status

approved