A187013 Number of isomorphism classes of simply embedded (i.e., loop-free and without parallel edges bounding a disk) quadrangulations of RP^2 of minimum degree 3 with n nodes and n-1 faces.

1, 0, 2, 3, 6, 12, 37, 95, 293, 923, 3086, 10504, 36954, 131590, 475793

Offset

4,3

Comments

Also the number of isomorphism classes of basic nets (polyhedra) on RP^2 with n-1 nodes and n faces.

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.

Links

Table of n, a(n) for n=4..18.

S. Yu. Orevkov, Basic nets in the projective plane

Crossrefs

Cf. A078666, A187014.

Sequence in context: A096746 A102970 A144771 * A295324 A054049 A276690

Adjacent sequences: A187010 A187011 A187012 * A187014 A187015 A187016

Keyword

nonn,more

Author

Stepan Orevkov, Aug 30 2013

Status

approved