A151580 Number of permutations of 1..n arranged in a circle with exactly 7 adjacent element pairs in decreasing order.

0, 8, 2223, 146080, 5007112, 116857368, 2112659718, 31852408056, 419567641380, 4982201574576, 54527214028669, 559001753070984, 5433944411838700, 50558500037520720, 453570522365097900, 3946487691743226960, 33461385366044612088, 277535329177185004536

Offset

7,2

Links

Andrew Howroyd, Table of n, a(n) for n = 7..500

Formula

a(n) = n*A001243(n-1). - Andrew Howroyd, May 05 2020

Crossrefs

Column k=7 of A334218.

Cf. A001243.

Sequence in context: A302380 A303101 A302952 * A173175 A268150 A325062

Adjacent sequences: A151577 A151578 A151579 * A151581 A151582 A151583

Keyword

nonn

Author

R. H. Hardin, May 21 2009

Extensions

Terms a(16) and beyond from Andrew Howroyd, May 05 2020

Status

approved