A151584 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 3 adjacent element pairs in decreasing order.

0, 36, 1088, 14220, 134928, 1093316, 8120064, 57280284, 391301840

Offset

2,2

Links

Table of n, a(n) for n=2..10.

Crossrefs

Sequence in context: A184292 A225830 A000809 * A233085 A215858 A103278

Adjacent sequences: A151581 A151582 A151583 * A151585 A151586 A151587

Keyword

nonn

Author

R. H. Hardin May 21 2009

Status

approved