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Number of connected one-sided arrangements of n pseudo-circles in the affine plane, in the sense that the union of the boundaries of the pseudo-circles is a connected set.
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%I #11 Feb 17 2019 23:01:44

%S 1,1,1,6,139,28643

%N Number of connected one-sided arrangements of n pseudo-circles in the affine plane, in the sense that the union of the boundaries of the pseudo-circles is a connected set.

%C Arrangements in A288559 that are connected, in the sense that the union of the (boundaries of the) pseudo-circles is a connected set.

%C These counts have not been reduced for mirror symmetry.

%C See A250001, the main entry for this problem, for further information.

%Y Cf. A250001, A275923, A275924, A288554-A288568.

%K nonn,more

%O 0,4

%A _N. J. A. Sloane_, Jun 13 2017, based on information supplied by _Jon Wild_ on Aug 31 2016