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A012083
arctanh(arcsin(tan(x)))=x+5/3!*x^3+129/5!*x^5+8133/7!*x^7+949281/9!*x^9...
0
1, 5, 129, 8133, 949281, 177127653, 48290752353, 18102997908453, 8931245615625921, 5609823664317348165, 4370983985597526359745, 4137308650120582099800453, 4676183786000402886175691745
OFFSET
0,2
FORMULA
a(n) ~ (2*n)! / (arctan(sin(1)))^(2*n+1). - Vaclav Kotesovec, Feb 05 2015
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[ArcTanh[ArcSin[Tan[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Nov 26 2014 *)
CROSSREFS
Sequence in context: A012022 A012176 A012187 * A012226 A281818 A332317
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved