Number of sets of subsets of {1..n} closed under union and intersection and covering all of the vertices.
A326909
Number of sets of subsets of {1..n} closed under union and intersection and covering all of the vertices.
Terms
- a(0) =2a(1) =2a(2) =7a(3) =45a(4) =500a(5) =9053a(6) =257151a(7) =11161244a(8) =725343385a(9) =69407094565
External references
- oeis: A326909