Triangle read by rows: T(n,k) is the number of permutations p of [n] in which the length of the longest initial segment avoiding the 123-pattern is equal to k.
A092583
Triangle read by rows: T(n,k) is the number of permutations p of [n] in which the length of the longest initial segment avoiding the 123-pattern is equal to k.
Terms
- a(0) =1a(1) =0a(2) =2a(3) =0a(4) =1a(5) =5a(6) =0a(7) =4a(8) =6a(9) =14a(10) =0a(11) =20a(12) =30a(13) =28a(14) =42a(15) =0a(16) =120a(17) =180a(18) =168a(19) =120a(20) =132a(21) =0a(22) =840a(23) =1260a(24) =1176a(25) =840a(26) =495a(27) =429a(28) =0a(29) =6720
External references
- oeis: A092583