A012054 arctan(sin(arctanh(x)))=x-1/3!*x^3+9/5!*x^5-225/7!*x^7+3345/9!*x^9...

1, -1, 9, -225, 3345, -893025, -36212775, -20892252225, -3614048241375, -1664630362370625, -584598534985164375, -327627617091486830625, -181787523574523506599375, -131875411531849225343390625

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcTan[Sin[ArcTanh[x]]], {x, 0, nn}], x]Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jan 23 2013 *)

Crossrefs

Sequence in context: A074190 A069075 A218659 * A067405 A063386 A063392

Adjacent sequences: A012051 A012052 A012053 * A012055 A012056 A012057

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Jan 23 2013

Status

approved