Number A(n,k) of set partitions of [n] such that j is member of block b only if b = 1 or at least one of j-1, ..., j-k is member of a block >= b-1; square array A(n,k), n>=0, k>=0, read by antidiagonals.
A287641
Number A(n,k) of set partitions of [n] such that j is member of block b only if b = 1 or at least one of j-1, ..., j-k is member of a block >= b-1; square array A(n,k), n>=0, k>=0, read by antidiagonals.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =2a(9) =1a(10) =1a(11) =1a(12) =2a(13) =5a(14) =1a(15) =1a(16) =1a(17) =2a(18) =5a(19) =14a(20) =1a(21) =1a(22) =1a(23) =2a(24) =5a(25) =15a(26) =42a(27) =1a(28) =1a(29) =1
External references
- oeis: A287641