Irregular triangle read by rows: T(n,k) is the number of permutations of two copies of 1..n with the sum of the distances between equal numbers having total value n + 2*k, 0 <= k <= n*(n-1)/2.
A335009
Irregular triangle read by rows: T(n,k) is the number of permutations of two copies of 1..n with the sum of the distances between equal numbers having total value n + 2*k, 0 <= k <= n*(n-1)/2.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =6a(4) =24a(5) =24a(6) =36a(7) =24a(8) =144a(9) =288a(10) =480a(11) =576a(12) =432a(13) =576a(14) =120a(15) =960a(16) =2880a(17) =6000a(18) =10560a(19) =12960a(20) =18720a(21) =18000a(22) =17280a(23) =11520a(24) =14400a(25) =720a(26) =7200a(27) =28800a(28) =74880a(29) =161280
External references
- oeis: A335009