A009432 Expansion of e.g.f. log(1+x)/cosh(sinh(x)).

0, 1, -1, -1, 0, 9, -45, 447, -2744, 17553, -171585, 1757535, -19723176, 245370969, -3189613245, 44636677407, -674857335120, 10851333193249, -185485926579489, 3356664148618047, -64009236131219760, 1284480775318317225

Offset: 0

Author

R. H. Hardin

Keywords

• sign
• easy

Links

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

Crossrefs

Cf. A009405 - A009420, A009422 - A009431, A009433 - A009439.

Programs

Magma

R:=PowerSeriesRing(Rationals(), 30);
[0] cat Coefficients(R!(Laplace( Log(1+x)/Cosh(Sinh(x)) ))); // G. C. Greubel, Sep 08 2023

Mathematica

With[{m=30}, CoefficientList[Series[Log[1+x]/Cosh[Sinh[x]], {x,0,m}], x]*Range[0, m]!] (* modified by G. C. Greubel, Sep 08 2023 *)

SageMath

def A009432_list(prec):
    P. = PowerSeriesRing(QQ, prec)
    return P( log(1+x)/cosh(sinh(x)) ).egf_to_ogf().list()
A009432_list(31) # G. C. Greubel, Sep 08 2023

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997