This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A288564 #13 Jul 09 2025 04:44:33 %S A288564 1,1,2,11,183,30408 %N A288564 Number of connected one-sided arrangements of n pseudo-circles in the affine plane, in the sense that the union of the solid pseudo-circles is a connected set. %C A288564 Arrangements in A288563 that are connected (in the sense that the union of the solid pseudo-circles is a connected set). %C A288564 These counts have not been reduced for mirror symmetry. %C A288564 See A250001, the main entry for this problem, for further information. %Y A288564 Cf. A250001, A275923, A275924, A288554-A288568. %K A288564 nonn,more %O A288564 0,3 %A A288564 _N. J. A. Sloane_, Jun 13 2017, based on information supplied by _Jon Wild_ on Aug 31 2016