%I #6 May 24 2021 16:14:02
%S 1,2,4,-2,-64,-238,1024,18478,64256,-1078558,-16672256,-22614242,
%T 2401458176,32373060722,-117093134336,-9756500186162,-106877784162304,
%U 1553450981649602,64518260702838784,465844716994278718
%N Expansion of (1+sin(x)+sin(x)^2)/(1-sin(x)+sin(x)^2).
%t With[{nn=20},CoefficientList[Series[(1+Sin[x]+Sin[x]^2)/(1-Sin[x]+ Sin[x]^2), {x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, May 24 2021 *)
%K sign
%O 0,2
%A _N. J. A. Sloane_.