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A012071 arctanh(arcsin(arcsin(x)))=x+4/3!*x^3+92/5!*x^5+5160/7!*x^7+532880/9!*x^9... 0
1, 4, 92, 5160, 532880, 87726464, 21073486912, 6956206790528, 3020988238174464, 1670080968001854464, 1145224829994344492032, 953987340413779610175488, 948917210079076407043002368 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

a(n) ~ (2*n)! / (sin(sin(1)))^(2*n+1). - Vaclav Kotesovec, Feb 05 2015

MATHEMATICA

nn = 20; Table[(CoefficientList[Series[ArcTanh[ArcSin[ArcSin[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 05 2015 *)

CROSSREFS

Sequence in context: A003737 A265238 A322769 * A012217 A012135 A221287

Adjacent sequences:  A012068 A012069 A012070 * A012072 A012073 A012074

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified May 21 14:52 EDT 2022. Contains 353917 sequences. (Running on oeis4.)