A013179 cos(arctanh(x)+arctan(x))=1-4/2!*x^2+16/4!*x^4-640/6!*x^6+21760/8!*x^8...

1, -4, 16, -640, 21760, -2291200, 223436800, -44438118400, 8725110784000, -2796896567296000, 926039081943040000, -435519369139978240000, 218626979887002419200000, -141711151230417633280000000

Offset

0,2

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Cos[ArcTanh[x]+ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Ray Chandler, Nov 29 2016 *)

Crossrefs

Sequence in context: A013006 A013001 A218644 * A144177 A300315 A361196

Adjacent sequences: A013176 A013177 A013178 * A013180 A013181 A013182

Keyword

sign

Author

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

Status

approved