Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with meet {{1},...,{n}} and join of length k.
A318389
Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with meet {{1},...,{n}} and join of length k.
Terms
- a(0) =1a(1) =2a(2) =1a(3) =8a(4) =6a(5) =1a(6) =56a(7) =44a(8) =12a(9) =1a(10) =552a(11) =440a(12) =140a(13) =20a(14) =1a(15) =7202a(16) =5632a(17) =1920a(18) =340a(19) =30a(20) =1a(21) =118456a(22) =89278a(23) =31192a(24) =6160a(25) =700a(26) =42a(27) =1a(28) =2369922a(29) =1708016
External references
- oeis: A318389