A151589 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 8 adjacent element pairs in decreasing order.

0, 5, 105372, 92123514, 25367820672, 3777055329267

Offset

4,2

Links

Table of n, a(n) for n=4..9.

Crossrefs

Sequence in context: A133381 A366270 A236066 * A243114 A038027 A237641

Adjacent sequences: A151586 A151587 A151588 * A151590 A151591 A151592

Keyword

nonn

Author

R. H. Hardin May 21 2009

Status

approved