A009722 Expansion of tan(tanh(x)*tan(x))/2.

1, 176, 570496, 9223556096, 460993706622976, 55266063875773300736, 13556412676746128524312576, 6098119622978353294582319415296, 4642750780653941150969313976486199296

Offset

0,2

Links

Table of n, a(n) for n=0..8.

Mathematica

With[{nn=40}, Take[CoefficientList[Series[Tan[Tanh[x]*Tan[x]]/2, {x, 0, nn}], x] Range[0, nn-2]!, {3, -1, 4}]] (* Harvey P. Dale, Oct 24 2017 *)

Crossrefs

A012669.

Sequence in context: A298250 A184293 A159426 * A159442 A046189 A278198

Adjacent sequences: A009719 A009720 A009721 * A009723 A009724 A009725

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested 03/97.

Name corrected by Vaclav Kotesovec, Jan 23 2015

Prior Mathematica program replaced by Harvey P. Dale, Oct 24 2017

Status

approved