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%I #15 Nov 09 2023 12:13:52
%S 1,1,1,2,8,278,145058,447905202
%N Number of non-isomorphic arrangements of n pairwise intersecting pseudo-circles on a sphere, reduced for mirror symmetry.
%C The list of arrangements is available online on the Homepage of Pseudocircles (see below) and a detailed description for the enumeration can be found in Arrangements of Pseudocircles: On Circularizability (see below).
%H S. Felsner and M. Scheucher <a href="http://www3.math.tu-berlin.de/pseudocircles/">Homepage of Pseudocircles</a>
%H S. Felsner and M. Scheucher, <a href="http://arxiv.org/abs/1712.02149">Arrangements of Pseudocircles: On Circularizability</a>, arXiv:1712.02149 [cs.CG], 2017.
%H Yan Alves Radtke, Stefan Felsner, Johannes Obenaus, Sandro Roch, Manfred Scheucher, and Birgit Vogtenhuber, <a href="https://arxiv.org/abs/2310.19711">Flip Graph Connectivity for Arrangements of Pseudolines and Pseudocircles</a>, arXiv:2310.19711 [math.CO], 2023. See p. 41.
%F a(n) = 2^(\Theta(n^2)). (cf. Arrangements of Pseudocircles: On Circularizability)
%Y Cf. A250001, A275923, A275924, A288554-A288568, A296407-A296412, A006248.
%K nonn,more
%O 0,4
%A _Manfred Scheucher_, Dec 11 2017