login
A009068
Expansion of e.g.f. cos(tan(tan(x))), even terms only.
1
1, -1, -15, -513, -31007, -2881089, -376412847, -64825974593, -13951231536191, -3556538162237313, -998391201911168335, -261420586488162589057, -14787500346745601332575, 86170769393986400590463039
OFFSET
0,3
LINKS
MATHEMATICA
With[{nmax = 60}, CoefficientList[Series[Cos[Tan[Tan[x]]], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* G. C. Greubel, Jul 24 2018 *)
PROG
(PARI) x='x+O('x^60); v=Vec(serlaplace(cos(tan(tan(x))))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 24 2018
CROSSREFS
Sequence in context: A218632 A218235 A212739 * A268960 A157166 A074040
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved