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Number of isomorphism classes of simple quadrangulations of the sphere having n vertices and n-2 faces, with orientation-reversing isomorphisms permitted.
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%I #21 Feb 21 2020 19:45:38

%S 1,1,2,3,9,18,62,198,803,3378,15882,77185,393075,2049974,10938182,

%T 59312272,326258544,1815910231,10213424233,57974895671,331820721234,

%U 1913429250439,11109119321058,64901418126997

%N Number of isomorphism classes of simple quadrangulations of the sphere having n vertices and n-2 faces, with orientation-reversing isomorphisms permitted.

%H G. Brinkmann, S. Greenberg, C. Greenhill, B. D. McKay, R. Thomas, and P. Wollan, <a href="http://dx.doi.org/10.1016/j.disc.2005.10.005">Generation of simple quadrangulations of the sphere</a>, Discr. Math., 305 (2005), 33-54.

%H Gunnar Brinkmann and Brendan McKay, <a href="http://users.cecs.anu.edu.au/~bdm/plantri/">plantri and fullgen</a> programs for generation of certain types of planar graph.

%H Gunnar Brinkmann and Brendan McKay, <a href="/A000103/a000103_1.pdf">plantri and fullgen</a> programs for generation of certain types of planar graph [Cached copy, pdf file only, no active links, with permission]

%H J. Cantarella, H. Chapman, M. Mastin, <a href="https://arxiv.org/abs/1512.05749">Knot Probabilities in Random Diagrams</a>, arXiv preprint arXiv:1512.05749 [math.GT], 2015. See Tables 1.

%H CombOS - Combinatorial Object Server, <a href="http://combos.org/plantri">generate planar graphs</a>

%H Paul Jungeblut, <a href="https://i11www.iti.kit.edu/_media/teaching/theses/ma-jungeblut-19.pdf">Edge Guarding Plane Graphs</a>, Master Thesis, Karlsruhe Institute of Technology (Germany, 2019).

%H Sage, <a href="http://sagemanifolds.obspm.fr/doc/reference/graphs/sage/graphs/graph_generators.html">Common Graphs</a>

%Y Cf. A078666, A007022, A002880.

%K nonn

%O 4,3

%A _N. J. A. Sloane_, Jan 07 2006