A012734 arctanh(arctanh(x)*arctan(x))=2/2!*x^2+448/6!*x^6+2380032/10!*x^10...

2, 448, 2380032, 69695846400, 6697099792220160, 1606188416621920911360, 810882197441673837894696960, 766865924510666637669136261447680

Offset

0,1

Links

Table of n, a(n) for n=0..7.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcTanh[ArcTanh[x]*ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {3, -1, 4}]] (* Ray Chandler, Nov 28 2016 *)

Crossrefs

Sequence in context: A118710 A159513 A012730 * A363699 A099686 A066152

Adjacent sequences: A012731 A012732 A012733 * A012735 A012736 A012737

Keyword

nonn

Author

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

Status

approved