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%I #5 Dec 27 2023 22:56:28
%S 0,4,11565,2580588,229630758,12719963448,531411968223,18510889687040
%N Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 6 adjacent element pairs in decreasing order.
%K nonn
%O 3,2
%A _R. H. Hardin_, May 21 2009