Total number of permutations on {1,2,...,n} that have a unique longest increasing subsequence and a unique longest decreasing subsequence.
A258683
Total number of permutations on {1,2,...,n} that have a unique longest increasing subsequence and a unique longest decreasing subsequence.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =0a(4) =2a(5) =16a(6) =120a(7) =938a(8) =8014a(9) =74060a(10) =748628a(11) =8163156a(12) =96429784
External references
- oeis: A258683