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The number of different classes of 2-dimensional convex lattice polytopes having volume n/2 up to unimodular equivalence.
6

%I #41 Oct 11 2023 08:42:33

%S 1,2,3,7,6,13,13,27,26,44,43,83,81,122,136,208,215,317,341,490,542,

%T 710,778,1073,1186,1519,1708,2178,2405,3042,3408,4247,4785,5782,6438,

%U 7870,8833,10560,11857,14131,15733,18636,20773,24381,27353,31764,35284,41081,45791,52762

%N The number of different classes of 2-dimensional convex lattice polytopes having volume n/2 up to unimodular equivalence.

%C Lattice polytopes up to the equivalence relation used here are also called toric diagrams, see references below. - _Andrey Zabolotskiy_, May 10 2019

%C Liu & Zong give a(7) = 11, and others use their list, but their list lacks polygons No. 3 and 4 from Balletti's file 2-polytopes/v7.txt. - _Andrey Zabolotskiy_, Dec 28 2021

%H Gabriele Balletti, <a href="https://github.com/gabrieleballetti/small-lattice-polytopes">Dataset of "small" lattice polytopes</a>. Beware that the vertices are not always listed in sorted order around the polygon boundary (clockwise or counterclockwise).

%H Gabriele Balletti, <a href="https://doi.org/10.1007/s00454-020-00187-y">Enumeration of lattice polytopes by their volume</a>, Discrete Comput. Geom., 65 (2021), 1087-1122; arXiv:<a href="https://arxiv.org/abs/1811.03357">1103.0103</a> [math.CO], 2018.

%H Sebastián Franco, Yang-Hui He, Chuang Sun and Yan Xiao, <a href="https://doi.org/10.1142/S0217751X17501421">A comprehensive survey of brane tilings</a>, Int. J. Mod. Phys. A, 32 (2017), 1750142, <a href="https://arxiv.org/abs/1702.03958">arXiv:1702.03958</a> [hep-th], 2017.

%H Heling Liu and Chuanming Zong, <a href="https://doi.org/10.1515/advgeom.2011.031">On the classification of convex lattice polytopes</a>, Adv. Geom., 11 (2011), 711-729, <a href="https://arxiv.org/abs/1103.0103">arXiv:1103.0103</a> [math.MG], 2011. See table at p. 8.

%H Yan Xiao, <a href="https://openaccess.city.ac.uk/id/eprint/22113">Quivers, Tilings and Branes</a>, City, University of London, 2018. See Tables 3.2-3.7.

%Y Cf. A126587, A003051 (triangles only), A322343, A366409.

%K nonn

%O 1,2

%A _Jonathan Vos Post_, Mar 01 2011

%E a(8) from Yan Xiao added by _Andrey Zabolotskiy_, May 10 2019

%E Name edited, a(7) corrected, a(9)-a(50) added using Balletti's data by _Andrey Zabolotskiy_, Dec 28 2021