

A325595


Number of symmetric Euclidean pseudoorder types: nondegenerate abstract order types of configurations of n points in the plane with a nontrivial automorphism.


2



0, 1, 1, 2, 3, 12, 30, 230, 849, 13434, 76200, 2392066
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OFFSET

1,4


LINKS

S. Felsner and J. E. Goodman, Pseudoline Arrangements. In: Toth, O'Rourke, Goodman (eds.) Handbook of Discrete and Computational Geometry, 3rd edn. CRC Press, 2018.


FORMULA

Asymptotics: a(n) = 2^(Theta(n^2)). This is BachmannLandau notation, that is, there are constants n_0, c, and d, such that for every n >= n_0 the inequality 2^{c n^2} <= a(n) <= 2^{d n^2} is satisfied. For more information see e.g. the Handbook of Discrete and Computational Geometry.  Manfred Scheucher, Sep 12 2019


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



