A151585 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 4 adjacent element pairs in decreasing order.

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

Offset

2,2

Links

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

Crossrefs

Sequence in context: A167058 A167067 A324443 * A286525 A030250 A145231

Adjacent sequences: A151582 A151583 A151584 * A151586 A151587 A151588

Keyword

nonn

Author

R. H. Hardin May 21 2009

Status

approved