Number of isomorphism classes of simple quadrangulations of the sphere having n vertices and n-2 faces, minimal degree 3, with orientation-reversing isomorphisms forbidden.

A113203

Number of isomorphism classes of simple quadrangulations of the sphere having n vertices and n-2 faces, minimal degree 3, with orientation-reversing isomorphisms forbidden.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =4a(5) =3a(6) =16a(7) =26a(8) =99a(9) =256a(10) =895a(11) =2789a(12) =9740a(13) =32799a(14) =115024a(15) =401180a(16) =1421170a(17) =5046539a(18) =18066772a(19) =64940825a(20) =234712099a(21) =851801048a(22) =3104690139a(23) =11358900851a(24) =41710948878a(25) =153684688127a(26) =568079430741

External references