Related to graded partially ordered sets.

A001828

Related to graded partially ordered sets.

Terms

    a(0) =1a(1) =5a(2) =33a(3) =287a(4) =3309a(5) =50975a(6) =1058493a(7) =29885567a(8) =1156711869a(9) =61815727295

External references