Number of acyclic digraphs with n unlabeled nodes.

A003087

Number of acyclic digraphs with n unlabeled nodes.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =31a(5) =302a(6) =5984a(7) =243668a(8) =20286025a(9) =3424938010

External references