%I A054479
%S A054479 1,0,6,120,6300,514080,62785800,10676746080,2413521910800,
%T A054479 700039083744000,253445583029839200,112033456760809584000,
%U A054479 59382041886244720843200,37175286835046004765120000
%N A054479 Number of sets of cycle graphs of 2n nodes where the 2-colored edges 
               alternate colors.
%C A054479 Also number of permutations in the symmetric group S_2n in which cycle 
               lengths are even and greater than 2, cf. A130915. - Vladeta Jovovic 
               (vladeta(AT)eunet.rs), Aug 25 2007
%F A054479 If b(2n)=a(n) then egf of b is 1/(sqrt(e^x^2 * (1-x^2))).
%Y A054479 Cf. A001147, A001818, A053871.
%Y A054479 Sequence in context: A012846 A012641 A012795 this_sequence A012475 A053777 
               A023199
%Y A054479 Adjacent sequences: A054476 A054477 A054478 this_sequence A054480 A054481 
               A054482
%K A054479 nonn
%O A054479 0,3
%A A054479 Christian G. Bower (bowerc(AT)usa.net), Mar 29 2000