A013114 sech(arcsinh(x)+arctan(x))=1-4/2!*x^2+104/4!*x^4-6790/6!*x^6...

1, -4, 104, -6790, 827480, -162019450, 46518314300, -18413421592150, 9610889961530000, -6395770003655763250, 5285420552751908562500, -5310341702734086669088750, 6374725468204682712703775000

Offset

0,2

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[ArcSinh[x]+ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 21 2020 *)

Crossrefs

Sequence in context: A012958 A012984 A202683 * A281430 A354174 A158114

Adjacent sequences: A013111 A013112 A013113 * A013115 A013116 A013117

Keyword

sign

Author

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

Status

approved