A009069 Expansion of e.g.f. cos(tan(tanh(x))), even terms only.

1, -1, 1, 47, -1343, 8671, 2436545, -249528945, 10176663169, 1606374108095, -482969577637247, 59264468409177327, 4209524591120115521, -4541227341778149686881, 1235175100383899185304129

Offset

0,4

Links

G. C. Greubel, Table of n, a(n) for n = 0..242

Mathematica

With[{nmax = 60}, CoefficientList[Series[Cos[Tan[Tanh[x]]], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* G. C. Greubel, Jul 24 2018 *)

Prog

(PARI) x='x+O('x^50); v=Vec(serlaplace(cos(tan(tanh(x))))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 24 2018

Crossrefs

Sequence in context: A182019 A270501 A047911 * A348805 A285237 A157359

Adjacent sequences: A009066 A009067 A009068 * A009070 A009071 A009072

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved