A009727 - OEIS

A009727

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

1, -1, 21, 27, 6121, 153559, 13064637, 996722035, 114653539281, 15657589156655, 2678537704263781, 548432789294290763, 133426766351448919481, 37955932970963263679495, 12491453691407386059683341

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

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

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Tan[x]*Cos[Sin[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Sep 09 2025 *)

CROSSREFS

Sequence in context: A114168 A103083 A120735 * A337702 A168105 A227936

Adjacent sequences: A009724 A009725 A009726 * A009728 A009729 A009730

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Previous Mathematica program replaced by Harvey P. Dale, Sep 09 2025

STATUS

approved