A012984 sech(arctan(x)+sin(x))=1-4/2!*x^2+104/4!*x^4-6694/6!*x^6...

1, -4, 104, -6694, 804632, -155439834, 44039778108, -17203328738054, 8861587113743248, -5819908969853023218, 4746578915592187681348, -4706547390563027522258046, 5575973518183361179212558488

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[ArcTan[x]+Sin[x]], {x, 0, nn}], x]Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 22 2012 *)

Crossrefs

Sequence in context: A013054 A024262 A012958 * A202683 A013114 A281430

Adjacent sequences: A012981 A012982 A012983 * A012985 A012986 A012987

Keyword

sign

Author

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

Status

approved