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A012042 arctanh(sin(arcsinh(x)))=x+4/5!*x^5-80/7!*x^7+4240/9!*x^9-342400/11!*x^11... 1
1, 0, 4, -80, 4240, -342400, 41806400, -7093216000, 1601470624000, -464003651072000, 167847611351680000, -74143433704737280000, 39275771932443138560000, -24575763662119940608000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..200

FORMULA

a(n) ~ c * (-1)^n * (2*n)! / sqrt(n), where c = 0.22485031987421343130846684736559... . - Vaclav Kotesovec, Feb 03 2015

MATHEMATICA

nn = 20; Table[(CoefficientList[Series[ArcTanh[Sin[ArcSinh[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 03 2015 *)

CROSSREFS

Sequence in context: A012923 A012922 A013090 * A013139 A013007 A013008

Adjacent sequences:  A012039 A012040 A012041 * A012043 A012044 A012045

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified January 19 06:18 EST 2022. Contains 350464 sequences. (Running on oeis4.)