Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} whose shortest block is of length k (1 <= k <= n). A block of a permutation is a maximal sequence of consecutive integers which appear in consecutive positions. For example, the permutation 4512367 has 3 blocks: 45, 123, and 67. Its shortest block has length 2.
A184180
Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} whose shortest block is of length k (1 <= k <= n). A block of a permutation is a maximal sequence of consecutive integers which appear in consecutive positions. For example, the permutation 4512367 has 3 blocks: 45, 123, and 67. Its shortest block has length 2.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =5a(4) =0a(5) =1a(6) =22a(7) =1a(8) =0a(9) =1a(10) =117a(11) =2a(12) =0a(13) =0a(14) =1a(15) =713a(16) =5a(17) =1a(18) =0a(19) =0a(20) =1a(21) =5026a(22) =11a(23) =2a(24) =0a(25) =0a(26) =0a(27) =1a(28) =40285a(29) =31
External references
- oeis: A184180