A013000 arctan(arctan(x)+tan(x))=2*x-16/3!*x^3+808/5!*x^5-99328/7!*x^7...

2, -16, 808, -99328, 22756480, -8373489408, 4518380796928, -3361577372366848, 3297920024665948160, -4125214890387616169984, 6407889739355365222383616, -12101572905129973895312965632

Offset

0,1

Links

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

Mathematica

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

Crossrefs

Sequence in context: A013137 A013990 A013005 * A013178 A306000 A084595

Adjacent sequences: A012997 A012998 A012999 * A013001 A013002 A013003

Keyword

sign

Author

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

Extensions

Corrected definition - N. J. A. Sloane, Dec 17 2011

Status

approved