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A009509 Expansion of sin(tan(x))/cos(x). 0
1, 4, 32, 264, -9216, -1548032, -190744448, -25395878400, -3862395551744, -674521189158912, -133945803441307648, -29717777068093669376, -7172117320170458939392, -1797012698406108143681536 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sin[Tan[x]]/Cos[x], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Dec 23 2017 *)

CROSSREFS

Sequence in context: A300177 A092811 A013731 * A036725 A065089 A113329

Adjacent sequences:  A009506 A009507 A009508 * A009510 A009511 A009512

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Prior Mathematica program replaced by Harvey P. Dale, Dec 23 2017

STATUS

approved

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Last modified December 6 13:05 EST 2021. Contains 349563 sequences. (Running on oeis4.)