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A012541 arctanh(sinh(x)*arcsin(x))=2/2!*x^2+8/4!*x^4+320/6!*x^6+15808/8!*x^8... 0
0, 2, 8, 320, 15808, 1671808, 242521600, 52294963968, 14823920529408, 5496196568825856, 2548323017071149056, 1453790822661022908416, 997862723859007908085760, 812410035086507459409412096 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

a(n) ~ (2*n-1)! / r^(2*n), where r = 0.858737427017558097934130835838437454788... is the root of the equation sinh(r)*arcsin(r) = 1. - Vaclav Kotesovec, Feb 05 2015

MATHEMATICA

With[{nn=30}, Flatten[{0, Take[CoefficientList[Series[ArcTanh[Sinh[x]ArcSin[x]], {x, 0, nn}], x] Range[0, nn]!, {3, -1, 2}]}]] (* Harvey P. Dale, Oct 31 2013 *)

CROSSREFS

Sequence in context: A217728 A013086 A012536 * A054943 A013135 A012999

Adjacent sequences:  A012538 A012539 A012540 * A012542 A012543 A012544

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

Prepended missing a(0)=0 from Vaclav Kotesovec, Feb 05 2015

STATUS

approved

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Last modified September 29 18:39 EDT 2022. Contains 357090 sequences. (Running on oeis4.)