%I #13 Nov 21 2013 12:46:00
%S 1,0,-3,-30,-483,-12660,-492063,-26407290,-1854592743,-162954226920,
%T -17150991170523,-2051454240374550,-254425037609483403,
%U -24186909676571913180,3098088521295623020617
%N E.g.f. cos(log(cos(x))), even powers only.
%F For n>1, a(n) appears to be divisible by 3, and the highest exponent of 2 in a(2m+1) seems to be A001511(m). - _Ralf Stephan_, Aug 14 2013
%t With[{nn=30},Take[CoefficientList[Series[Cos[Log[Cos[x]]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Aug 29 2011 *)
%K sign
%O 0,3
%A Patrick Demichel (patrick.demichel(AT)hp.com)