A012835 arctan(sec(x)*tanh(x))=x-1/3!*x^3+25/5!*x^5-761/7!*x^7+42065/9!*x^9...

1, -1, 25, -761, 42065, -3898321, 521329705, -96017526281, 23356125062945, -7240133620964641, 2786977252450841785, -1304375789021987253401, 729394652578427432666225, -480281453260247282387992561

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcTan[Sec[x]Tanh[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jul 30 2020 *)

Crossrefs

Sequence in context: A246906 A286439 A123835 * A277584 A223228 A132540

Adjacent sequences: A012832 A012833 A012834 * A012836 A012837 A012838

Keyword

sign

Author

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

Status

approved