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
Keywords
Links
- Andrew Howroyd, Table of n, a(n) for n = 7..500
Formula
a(n) = n*A001243(n-1). - Andrew Howroyd, May 05 2020
Extensions
Terms a(16) and beyond from Andrew Howroyd, May 05 2020