OFFSET
0,6
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Log[1+x]/Cosh[Tanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jun 19 2013 *)
PROG
(Magma)
R<x>:=PowerSeriesRing(Rationals(), 30);
[0] cat Coefficients(R!(Laplace( Log(1+x)/Cosh(Tanh(x)) ))); // G. C. Greubel, Sep 06 2023
(SageMath)
def A009434_list(prec):
P.<x> = PowerSeriesRing(QQ, prec)
return P( log(1+x)/cosh(tanh(x)) ).egf_to_ogf().list()
A009434_list(40) # G. C. Greubel, Sep 06 2023
(PARI) my(x='x+O('x^30)); concat([0], Vec(serlaplace(log(1+x)/cosh(tanh(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, Jun 19 2013
STATUS
approved