Number of down-arrow-indecomposable topologies on n labeled points.

A247659

Number of down-arrow-indecomposable topologies on n labeled points.

Terms

    a(0) =1a(1) =3a(2) =22a(3) =292a(4) =6120a(5) =193594a(6) =9070536a(7) =622336756a(8) =61915861962

External references