A012769 tan(cosh(x)*arctan(x))=x+3/3!*x^3+45/5!*x^5+1071/7!*x^7+69177/9!*x^9...

1, 3, 45, 1071, 69177, 3986939, 609782693, 60159520487, 18315680711153, 2425226987446387, 1432393396034388637, 194035475753231168543, 248503763037617443112745, 18849742079674987910368107

Offset

0,2

Comments

Note that a(15) is negative. - Vaclav Kotesovec, Feb 07 2015

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..200

Mathematica

nn = 20; Table[(CoefficientList[Series[Tan[ArcTan[x]*Cosh[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 07 2015 *)

Crossrefs

Sequence in context: A171080 A188681 A012827 * A302106 A361046 A241242

Adjacent sequences: A012766 A012767 A012768 * A012770 A012771 A012772

Keyword

sign

Author

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

Status

approved