A012190 Expansion of e.g.f. tanh(arctan(sin(x))), odd powers only.

1, -5, 121, -6845, 690481, -108594485, 24502918441, -7495966306925, 2984112329052001, -1498441322462840165, 926096248873419539161, -690670275602276172370205, 611502034169544516212107921

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Formula

E.g.f.: tanh(arctan(sin(x))), even terms only. - Harvey P. Dale, Sep 19 2011

Example

x-5/3!*x^3+121/5!*x^5-6845/7!*x^7+690481/9!*x^9...

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tanh[ArcTan[Sin[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Sep 19 2011 *)

Crossrefs

Sequence in context: A179299 A012179 A012026 * A012077 A012046 A012151

Adjacent sequences: A012187 A012188 A012189 * A012191 A012192 A012193

Keyword

sign

Author

Patrick Demichel

Extensions

Name edited by Michel Marcus, Aug 25 2025

Status

approved