OFFSET
0,2
LINKS
Iain Fox, Table of n, a(n) for n = 0..231 (first 101 terms from Vincenzo Librandi)
MAPLE
S:= series(tanh(tan(x)*x), x, 41):
seq(coeff(S, x, n)*n!, n=0..40, 2); # Robert Israel, Dec 21 2017
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Tanh[Tan[x]*x], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Oct 28 2013 *)
PROG
(PARI) first(n) = x='x+O('x^(2*n-1)); vecextract(Vec(serlaplace(tanh(tan(x)*x)), -2*n), (4^n - 1)/3) \\ Iain Fox, Dec 21 2017
CROSSREFS
KEYWORD
sign
AUTHOR
R. H. Hardin, Mar 15 1996
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Prior Mathematica program replaced by Harvey P. Dale, Oct 28 2013
STATUS
approved