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
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Prior Mathematica program corrected by Harvey P. Dale, Jan 28 2014
STATUS
approved