%I A067624
%S A067624 1,8,384,46080,10321920,3715891200,1961990553600,1428329123020800,
%T A067624 1371195958099968000,1678343852714360832000,2551082656125828464640000,
%U A067624 4714400748520531002654720000,10409396852733332453861621760000
%N A067624 Sqrt((1+cos(y))/2)= sum(n>=0,(-1)^n*y^(2n)/a(n)).
%F A067624 a(n)=A000165(2n) where A000165(k) are the double factorial numbers 2^k*k!=(2k)!! 
               [Corrected by Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 05 
               2009]
%F A067624 Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 06 
               2009: (Start)
%F A067624 a(n) = (4n)!! = 2^(2n)*(2n)!
%F A067624 (End)
%p A067624 for n from 0 to 30 by 2 do printf(`%d,`,2^(n)*(n)!) od:
%Y A067624 Cf. A000165.
%Y A067624 Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 06 
               2009: (Start)
%Y A067624 Appears in A162445, A061549 and A120738.
%Y A067624 (End)
%Y A067624 Sequence in context: A151932 A096205 A162445 this_sequence A096204 A153836 
               A151941
%Y A067624 Adjacent sequences: A067621 A067622 A067623 this_sequence A067625 A067626 
               A067627
%K A067624 nonn
%O A067624 0,2
%A A067624 Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 02 2002
%E A067624 More terms and Maple code from James A. Sellers (sellersj(AT)math.psu.edu), 
               Feb 11, 2002