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A009690 Expansion of tan(tan(sin(x))). 0
1, 3, 33, 739, 26913, 1416995, 101493889, 9507242819, 1129063338945, 165774337045955, 29468302949572705, 6227421783562843427, 1539946012373786340321, 439696998663601508079587 (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[Tan[Tan[Sin[x]]], {x, 0, nn}], x] Range[ 0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jun 01 2021 *)

CROSSREFS

Sequence in context: A233319 A003715 A247030 * A229513 A210833 A174488

Adjacent sequences:  A009687 A009688 A009689 * A009691 A009692 A009693

KEYWORD

nonn

AUTHOR

R. H. Hardin

EXTENSIONS

Extended and signs tested Mar 15 1997 by Olivier Gérard.

Prior Mathematica program replaced by Harvey P. Dale, Jun 01 2021

STATUS

approved

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Last modified January 23 11:42 EST 2022. Contains 350512 sequences. (Running on oeis4.)