A012219 arctanh(arctan(arcsinh(x)))=x-1/3!*x^3+17/5!*x^5-617/7!*x^7+44417/9!*x^9...

1, -1, 17, -617, 44417, -5210129, 909126033, -220910314809, 71341157623169, -29556627270426145, 15282372258542389905, -9645984260739983339273, 7298836347461102485422593, -6521512480584315170326457393

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcTanh[ArcTan[ArcSinh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Ray Chandler, Nov 28 2016 *)

Crossrefs

Sequence in context: A142744 A219090 A222615 * A349783 A219075 A265678

Adjacent sequences: A012216 A012217 A012218 * A012220 A012221 A012222

Keyword

sign

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Status

approved