Triangle read by rows: T(n-1,k), where n >= 2 and 1 <= k <= floor(n/2), is the number of permutations of (1, 2, ..., n) having k consecutive pairs but no consecutive sequences of length greater than 2.
A289632
Triangle read by rows: T(n-1,k), where n >= 2 and 1 <= k <= floor(n/2), is the number of permutations of (1, 2, ..., n) having k consecutive pairs but no consecutive sequences of length greater than 2.
Terms
- a(0) =1a(1) =2a(2) =9a(3) =1a(4) =44a(5) =9a(6) =265a(7) =66a(8) =3a(9) =1854a(10) =530a(11) =44a(12) =14833a(13) =4635a(14) =530a(15) =11a(16) =133496a(17) =44499a(18) =6180a(19) =265a(20) =1334961a(21) =467236a(22) =74165a(23) =4635a(24) =53a(25) =14684570a(26) =5339844a(27) =934472a(28) =74165a(29) =1854
External references
- oeis: A289632