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
KEYWORD
sign,easy
AUTHOR
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