A024281 - OEIS

%I #9 Apr 02 2017 15:35:13

%S 0,1,8,76,-2752,-553904,-77878912,-11370511424,-1778864822272,

%T -282582967817984,-36606453394757632,2075368674171759616,

%U 5791517230149348343808,4398620127304280971595776

%N Expansion of sin(tan(x)^2)/2.

%t 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 *)

%Y Cf. A009518.

%K sign

%O 0,3

%A _R. H. Hardin_

%E Extended with signs Mar 1997

%E Prior Mathematica program replaced by _Harvey P. Dale_, Feb 12 2016