A009438 Expansion of e.g.f. log(1+x)/exp(tan(x)).

0, 1, -3, 8, -32, 149, -831, 5340, -38744, 316161, -2846611, 28263960, -305651048, 3593550245, -45584631743, 622159233948, -9091059243792, 141783419182561, -2351573180823939, 41355560621409352, -768924714448510480

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Formula

a(n) ~ (n-1)! * (-1)^(n+1) * exp(tan(1)). - Vaclav Kotesovec, Jan 23 2015

Mathematica

With[{nn=20}, CoefficientList[Series[Log[1+x]/Exp[Tan[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jan 28 2014 *)

Prog

(Magma)
R<x>:=PowerSeriesRing(Rationals(), 30);
[0] cat Coefficients(R!(Laplace( Log(1+x)*Exp(-Tan(x)) ))); // G. C. Greubel, Sep 08 2023
(SageMath)
def A009438_list(prec):
    P.<x> = PowerSeriesRing(QQ, prec)
    return P( log(1+x)*exp(-tan(x)) ).egf_to_ogf().list()
A009438_list(31) # G. C. Greubel, Sep 08 2023

Crossrefs

Cf. A009405 - A009420, A009422 - A009437, A009439.

Sequence in context: A103939 A094610 A064316 * A321520 A321522 A328053

Adjacent sequences: A009435 A009436 A009437 * A009439 A009440 A009441

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Prior Mathematica program corrected by Harvey P. Dale, Jan 28 2014

Status

approved