A151587 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 6 adjacent element pairs in decreasing order.

0, 4, 11565, 2580588, 229630758, 12719963448, 531411968223, 18510889687040

Offset

3,2

Links

Table of n, a(n) for n=3..10.

Crossrefs

Sequence in context: A352497 A191592 A261821 * A193137 A280545 A134368

Adjacent sequences: A151584 A151585 A151586 * A151588 A151589 A151590

Keyword

nonn

Author

R. H. Hardin, May 21 2009

Status

approved