A151585 - OEIS

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A151585

Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 adjacent element pairs in decreasing order.

%I #3 Mar 31 2012 12:35:18

%S 0,3,976,44275,1046556,18098871,262962368,3438697635,42050013500

%N Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 adjacent element pairs in decreasing order.

%K nonn

%O 2,2

%A _R. H. Hardin_ May 21 2009