A012423 arctan(arctan(x)*sin(x))=2/2!*x^2-12/4!*x^4-50/6!*x^6+12936/8!*x^8...

0, 2, -12, -50, 12936, -643142, -60323780, 22895524678, -2421315237488, -864760878344718, 527455288321939204, -55917569000158790850, -108932420480580224669416, 83957330220575698201816746

Offset

0,2

Links

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

Mathematica

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

Crossrefs

Sequence in context: A218776 A241683 A341546 * A012427 A012695 A012382

Adjacent sequences: A012420 A012421 A012422 * A012424 A012425 A012426

Keyword

sign

Author

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

Status

approved