Number of unrooted triangulations of a quadrilateral with n internal nodes.

A005500

Number of unrooted triangulations of a quadrilateral with n internal nodes.

Terms

    a(0) =1a(1) =2a(2) =5a(3) =18a(4) =88a(5) =489a(6) =3071a(7) =20667a(8) =146381a(9) =1072760a(10) =8071728a(11) =61990477a(12) =484182622a(13) =3835654678a(14) =30757242535a(15) =249255692801

External references