A012802 sin(sec(x)*arctan(x))=x+20/5!*x^5-784/7!*x^7+26256/9!*x^9...

1, 0, 20, -784, 26256, -4466176, 435729216, -104111460608, 23261262303488, -7794968497086464, 2988775301503636480, -1434421552426973564928, 811112609409475303936000, -540598484103424258178285568

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sin[Sec[x]ArcTan[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, May 24 2013 *)

Crossrefs

Sequence in context: A203136 A034404 A179712 * A049214 A002455 A322890

Adjacent sequences: A012799 A012800 A012801 * A012803 A012804 A012805

Keyword

sign

Author

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

Status

approved