Number of nonisomorphic graded posets with 0 and 1 and non-uniform Hasse graph of rank n, with no 3-element antichain.

A208737

Number of nonisomorphic graded posets with 0 and 1 and non-uniform Hasse graph of rank n, with no 3-element antichain.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =7a(5) =37a(6) =175a(7) =778a(8) =3325a(9) =13837a(10) =56524a(11) =227866a(12) =909832a(13) =3607294a(14) =14227447a(15) =55894252a(16) =218937532a(17) =855650749a(18) =3338323915a(19) =13007422705a(20) =50631143323a(21) =196928737582a(22) =765495534433

External references