A009811 - OEIS

A009811

Expansion of tanh(tan(x))*sin(x).

0, 2, -4, -42, -456, 10154, 1263668, 74121726, 1582556016, -396499390126, -87145255604884, -10528569148387290, -379538283994219608, 201132350259244110074, 52827499211277672807332

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..14.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Tanh[Tan[x]] Sin[x], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, May 17 2021 *)

CROSSREFS

Sequence in context: A018312 A009547 A215921 * A364237 A009591 A009717

Adjacent sequences: A009808 A009809 A009810 * A009812 A009813 A009814

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Previous Mathematica program replaced by Harvey P. Dale, May 17 2021

STATUS

approved