A012206 sinh(arctan(arctan(x)))=x-3/3!*x^3+49/5!*x^5-1859/7!*x^7+119617/9!*x^9...

1, -3, 49, -1859, 119617, -10283171, 678311217, 246695568861, -270153706006015, 221300400903581245, -191103844337252819535, 185242544952868387351165, -204711474044267911803243455

Offset

0,2

Links

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

Mathematica

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

Crossrefs

Sequence in context: A337154 A300990 A062961 * A012094 A012059 A012166

Adjacent sequences: A012203 A012204 A012205 * A012207 A012208 A012209

Keyword

sign

Author

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

Status

approved