Number of unrooted triangulations with reflection symmetry of a disk with one internal node and n+3 nodes on the boundary.

A005508

Number of unrooted triangulations with reflection symmetry of a disk with one internal node and n+3 nodes on the boundary.

Terms

    a(0) =1a(1) =2a(2) =3a(3) =6a(4) =8a(5) =18a(6) =23a(7) =56a(8) =70a(9) =180a(10) =222a(11) =594a(12) =726a(13) =2002a(14) =2431a(15) =6864a(16) =8294a(17) =23868a(18) =28730a(19) =83980a(20) =100776a(21) =298452a(22) =357238a(23) =1069776a(24) =1277788a(25) =3863080a(26) =4605980a(27) =14040810a(28) =16715250a(29) =51325650

External references