Number of prime unlabeled topologies (i.e., prime homeomorphism classes) on n points.
A028855
Number of prime unlabeled topologies (i.e., prime homeomorphism classes) on n points.
Terms
- a(0) =3a(1) =9a(2) =27a(3) =139a(4) =691a(5) =4535
External references
- oeis: A028855