A187014 - OEIS

A187014

Number of isomorphism classes of simply embedded (i.e., loop-free and without parallel edges bounding a disk) bipartite quadrangulations of RP^2 of minimum degree 3 with n nodes and n-1 faces.

%I #21 Jul 16 2017 21:00:14

%S 0,0,1,2,3,7,22,57,174,554,1848,6291,22052,78361,282420

%N Number of isomorphism classes of simply embedded (i.e., loop-free and without parallel edges bounding a disk) bipartite quadrangulations of RP^2 of minimum degree 3 with n nodes and n-1 faces.

%C Also the number of isomorphism classes of homologically trivial basic nets on RP^2 with n-1 nodes and n faces.

%C Also the number of isomorphism classes of simple quadrangulations of the sphere of minimum degree 3 with 2n nodes and 2n-2 faces which admit an orientation reversing involution without fix nodes and fix edges such that the bipartite coloring is preserved under the involution.

%H S. Yu. Orevkov, <a href="http://arxiv.org/abs/1307.7377">Basic nets in the projective plane</a>

%Y Cf. A078666, A187013.

%K nonn,more

%O 4,4

%A _Stepan Orevkov_, Aug 30 2013