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A012219 arctanh(arctan(arcsinh(x)))=x-1/3!*x^3+17/5!*x^5-617/7!*x^7+44417/9!*x^9... 0
1, -1, 17, -617, 44417, -5210129, 909126033, -220910314809, 71341157623169, -29556627270426145, 15282372258542389905, -9645984260739983339273, 7298836347461102485422593, -6521512480584315170326457393 (list; graph; refs; listen; history; text; internal format)
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 * A219075 A265678 A200907

Adjacent sequences:  A012216 A012217 A012218 * A012220 A012221 A012222

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified October 21 18:05 EDT 2020. Contains 337919 sequences. (Running on oeis4.)