Number of even entries that are followed by a smaller entry in all permutations of {1,2,...,n}.
A145889
Number of even entries that are followed by a smaller entry in all permutations of {1,2,...,n}.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =24a(4) =96a(5) =1080a(6) =6480a(7) =80640a(8) =645120a(9) =9072000a(10) =90720000a(11) =1437004800a(12) =17244057600a(13) =305124019200
External references
- oeis: A145889