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A024281 Expansion of sin(tan(x)^2)/2. 1
0, 1, 8, 76, -2752, -553904, -77878912, -11370511424, -1778864822272, -282582967817984, -36606453394757632, 2075368674171759616, 5791517230149348343808, 4398620127304280971595776 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sin[Tan[x]^2]/2, {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Feb 12 2016 *)

CROSSREFS

Cf. A009518.

Sequence in context: A233827 A231286 A251927 * A232087 A105429 A225348

Adjacent sequences:  A024278 A024279 A024280 * A024282 A024283 A024284

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs Mar 1997

Prior Mathematica program replaced by Harvey P. Dale, Feb 12 2016

STATUS

approved

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Last modified February 19 18:31 EST 2018. Contains 299356 sequences. (Running on oeis4.)