A012182 cosh(tan(arctanh(x)))=1+1/2!*x^2+17/4!*x^4+721/6!*x^6+56545/8!*x^8...

1, 1, 17, 721, 56545, 7062241, 1283497841, 319471153457, 104260273696961, 43168502192389825, 22100367268731836881, 13703484478282258062481, 10117607255517016666964897, 8769262856125733251376413601

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Cosh[Tan[ArcTanh[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 21 2015 *)

Crossrefs

Sequence in context: A171198 A309410 A201311 * A012029 A012193 A128274

Adjacent sequences: A012179 A012180 A012181 * A012183 A012184 A012185

Keyword

nonn

Author

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

Status

approved