A024281 Expansion of sin(tan(x)^2)/2.

0, 1, 8, 76, -2752, -553904, -77878912, -11370511424, -1778864822272, -282582967817984, -36606453394757632, 2075368674171759616, 5791517230149348343808, 4398620127304280971595776

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