Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with meet of length k.
A318391
Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with meet of length k.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =1a(4) =9a(5) =15a(6) =1a(7) =21a(8) =90a(9) =113a(10) =1a(11) =45a(12) =375a(13) =1130a(14) =1153a(15) =1a(16) =93a(17) =1350a(18) =7345a(19) =17295a(20) =15125a(21) =1a(22) =189a(23) =4515a(24) =39550a(25) =161420a(26) =317625a(27) =245829a(28) =1a(29) =381
External references
- oeis: A318391