A013178 arctan(arctanh(x)+arctan(x))=2*x-16/3!*x^3+816/5!*x^5-100224/7!*x^7...

2, -16, 816, -100224, 23046912, -8501907456, 4600667731968, -3432263151550464, 3376634004034486272, -4235408050319799091200, 6597340706535893925101568, -12493980287273651231218728960

Offset

0,1

Links

Table of n, a(n) for n=0..11.

Mathematica

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

Crossrefs

Sequence in context: A013990 A013005 A013000 * A306000 A084595 A273193

Adjacent sequences: A013175 A013176 A013177 * A013179 A013180 A013181

Keyword

sign

Author

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

Status

approved