Number of distinct topologies on an n-set with exactly 6 open sets.

A281774

Number of distinct topologies on an n-set with exactly 6 open sets.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =6a(4) =72a(5) =630a(6) =4680a(7) =31206a(8) =193032a(9) =1131990a(10) =6386760a(11) =35025606a(12) =188061192a(13) =993760950a(14) =5187840840a(15) =26831095206a(16) =137770476552a(17) =703455087510

External references