a(n) is the number of n-element families of nonempty subsets of {1, ..., n} in which every number in 1..n appears the same nonzero number of times.
A392683
a(n) is the number of n-element families of nonempty subsets of {1, ..., n} in which every number in 1..n appears the same nonzero number of times.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =47a(4) =1201a(5) =96467a(6) =22683315
External references
- oeis: A392683