Triangle read by rows: T(n,k) is the number of permutations p of [n] such that the length of the longest 2-stack sortable initial segment of p is equal to k.
A094785
Triangle read by rows: T(n,k) is the number of permutations p of [n] such that the length of the longest 2-stack sortable initial segment of p is equal to k.
Terms
- a(0) =1a(1) =0a(2) =2a(3) =0a(4) =0a(5) =6a(6) =0a(7) =0a(8) =2a(9) =22a(10) =0a(11) =0a(12) =10a(13) =19a(14) =91a(15) =0a(16) =0a(17) =60a(18) =114a(19) =138a(20) =408a(21) =0a(22) =0a(23) =420a(24) =798a(25) =966a(26) =918a(27) =1938a(28) =0a(29) =0
External references
- oeis: A094785