A009713 Expansion of tan(tanh(tan(x))).

1, 2, 8, -176, -16384, -969728, -32455680, 4303626240, 1468506210304, 269552004300800, 24649152071991296, -7396863878894714880, -5630959968640999358464, -2114449853843696991076352

Offset

0,2

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tan[Tanh[Tan[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Aug 03 2016 *)

Crossrefs

Sequence in context: A076548 A167009 A350808 * A265597 A213200 A317794

Adjacent sequences: A009710 A009711 A009712 * A009714 A009715 A009716

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Prior Mathematica program replaced by Harvey P. Dale, Aug 03 2016

Status

approved