A009435 Expansion of e.g.f.: log(1+x)/cosh(x).

0, 1, -1, -1, 0, 29, -105, 139, -2072, 31737, -247545, 1824151, -22456104, 313750293, -3929185169, 51584719523, -793292190480, 13137192234225, -221862616530705, 3947317975733039, -75492532592047280, 1522475446731094285

Offset

0,6

Links

G. C. Greubel, Table of n, a(n) for n = 0..449

Formula

a(n) ~ (-1)^(n+1) * (n-1)! / cosh(1). - Vaclav Kotesovec, Oct 01 2014

Mathematica

With[{nn=30}, CoefficientList[Series[Log[1+x]/Cosh[x], {x, 0, nn}], x] Range[ 0, nn]!] (* Harvey P. Dale, Oct 01 2014 *)

Prog

(Magma)
R<x>:=PowerSeriesRing(Rationals(), 30);
[0] cat Coefficients(R!(Laplace( Log(1+x)/Cosh(x) ))); // G. C. Greubel, Sep 06 2023
(SageMath)
def A009435_list(prec):
    P.<x> = PowerSeriesRing(QQ, prec)
    return P( log(1+x)/cosh(x) ).egf_to_ogf().list()
A009435_list(40) # G. C. Greubel, Sep 06 2023
(PARI) my(x='x+O('x^30)); concat([0], Vec(serlaplace(log(1+x)/cosh(x)))) \\ Joerg Arndt, Sep 06 2023

Crossrefs

Cf. A009405 - A009420, A009422 - A009434, A009436 - A009439.

Sequence in context: A069472 A142138 A341550 * A126554 A258721 A009406

Adjacent sequences: A009432 A009433 A009434 * A009436 A009437 A009438

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Oct 01 2014

Status

approved