Number of distinct topologies on an n-set that have exactly 7 open sets.
A281775
Number of distinct topologies on an n-set that have exactly 7 open sets.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =54a(5) =780a(6) =7830a(7) =67620a(8) =535374a(9) =3992940a(10) =28483110a(11) =196316340a(12) =1317106494a(13) =8650141500a(14) =55853351190a(15) =355770438660
External references
- oeis: A281775