A012235 E.g.f.: arcsinh(arctan(arctanh(x)))=x-1/3!*x^3+17/5!*x^5-281/7!*x^7+24257/9!*x^9...

1, -1, 17, -281, 24257, -1331441, 275798481, -33388170825, 12274116245249, -2689107736315873, 1507045832586910737, -530866838718138680441, 415346005609060387325633, -217242204344672574488013521

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcSinh[ArcTan[ArcTanh[x]]], {x, 0, nn}], x]Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jun 05 2012 *)

Crossrefs

Sequence in context: A245940 A380131 A188063 * A196743 A196901 A171322

Adjacent sequences: A012232 A012233 A012234 * A012236 A012237 A012238

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Jun 05 2012

Status

approved