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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

%I

%S 1,4,92,5160,532880,87726464,21073486912,6956206790528,

%T 3020988238174464,1670080968001854464,1145224829994344492032,

%U 953987340413779610175488,948917210079076407043002368

%N arctanh(arcsin(arcsin(x)))=x+4/3!*x^3+92/5!*x^5+5160/7!*x^7+532880/9!*x^9...

%F a(n) ~ (2*n)! / (sin(sin(1)))^(2*n+1). - _Vaclav Kotesovec_, Feb 05 2015

%t 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 *)

%K nonn

%O 0,2

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

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Last modified July 4 16:52 EDT 2022. Contains 355081 sequences. (Running on oeis4.)