Number of permutations p of 1,2,...,n satisfying |p(i+5)-p(i)|<>5 for all 1<=i<=n-5.
A189256
Number of permutations p of 1,2,...,n satisfying |p(i+5)-p(i)|<>5 for all 1<=i<=n-5.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =24a(4) =120a(5) =672a(6) =4128a(7) =28992a(8) =231936a(9) =2088960a(10) =20434944a(11) =221871360a(12) =2645370624a(13) =34344038400a(14) =482103767040
External references
- oeis: A189256