A012071 arctanh(arcsin(arcsin(x)))=x+4/3!*x^3+92/5!*x^5+5160/7!*x^7+532880/9!*x^9...

1, 4, 92, 5160, 532880, 87726464, 21073486912, 6956206790528, 3020988238174464, 1670080968001854464, 1145224829994344492032, 953987340413779610175488, 948917210079076407043002368

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: A362511 A265238 A322769 * A012217 A012135 A221287

Adjacent sequences: A012068 A012069 A012070 * A012072 A012073 A012074

Keyword

nonn

Author

Patrick Demichel

Status

approved