A012205 arctan(arctan(arctan(x)))=x-6/3!*x^3+192/5!*x^5-14704/7!*x^7...

1, -6, 192, -14704, 2058624, -457982720, 148443124736, -66066559066112, 38672430452342784, -28812765976119148544, 26627757204719641296896, -29895731887419723149213696, 40082507396600200285753704448

Offset

0,2

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcTan[ArcTan[ArcTan[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Ray Chandler, Nov 28 2016 *)

Crossrefs

Sequence in context: A350873 A182788 A232214 * A156122 A281501 A283884

Adjacent sequences: A012202 A012203 A012204 * A012206 A012207 A012208

Keyword

sign

Author

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

Status

approved