Number of pairs of set partitions of {1,...,n} where every block of one is a subset or superset of some block of the other.
A322442
Number of pairs of set partitions of {1,...,n} where every block of one is a subset or superset of some block of the other.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =25a(4) =195a(5) =1894a(6) =22159a(7) =303769a(8) =4790858a(9) =85715595a(10) =1720097275a(11) =38355019080a(12) =942872934661
External references
- oeis: A322442