A012447 arctan(arctan(x)*tan(x))=2/2!*x^2-80/6!*x^6-2688/8!*x^8+260608/10!*x^10...

0, 2, 0, -80, -2688, 260608, 2928640, -463763456, -517376835584, 108823739498496, -2683131538178048, 5868236283429519360, -6862655376791380688896, 2738386568702639562817536

Offset

0,2

Links

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

Mathematica

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

Crossrefs

Sequence in context: A012647 A012334 A012451 * A136558 A156490 A216678

Adjacent sequences: A012444 A012445 A012446 * A012448 A012449 A012450

Keyword

sign

Author

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

Status

approved