Number of set-systems (finite sets of finite nonempty sets) with union {1,2,...,n} and intersection {}.

A318128

Number of set-systems (finite sets of finite nonempty sets) with union {1,2,...,n} and intersection {}.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =84a(4) =31478a(5) =2147000136

External references