Number of different, not necessarily connected, labeled trivalent diagrams of size n.

A121357

Number of different, not necessarily connected, labeled trivalent diagrams of size n.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =12a(4) =90a(5) =546a(6) =6156a(7) =81432a(8) =942012a(9) =15114780a(10) =294765336a(11) =5069224656a(12) =108842183352

External references