(1/16) times the number of permutations p of [n+2] such that |p(i+n) - p(i)| <> n for i in {1,2}.
A333804
(1/16) times the number of permutations p of [n+2] such that |p(i+n) - p(i)| <> n for i in {1,2}.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =5a(4) =34a(5) =258a(6) =2172a(7) =20220a(8) =207000a(9) =2315880a(10) =28143360a(11) =369411840a(12) =5210956800a(13) =78636096000
External references
- oeis: A333804