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A012228

arctanh(arctan(tanh(x)))=x-2/3!*x^3+24/5!*x^5-944/7!*x^7+77952/9!*x^9...

1, -2, 24, -944, 77952, -10623744, 2145104896, -602082207744, 224357319278592, -107165894175948800, 63836869263529082880, -46390243522547859062784, 40392288941602607862906880

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

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

MATHEMATICA

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

CROSSREFS

Sequence in context: A137274 A002032 A015212 * A062029 A122551 A136524

Adjacent sequences: A012225 A012226 A012227 * A012229 A012230 A012231

KEYWORD

sign

AUTHOR

Patrick Demichel

STATUS

approved

URL: https://oeis.org/A012228

⇱ A012228 - OEIS