A288562 - OEIS

%I #15 May 10 2018 03:29:44

%S 1,1,1,4,45,5108,4598809

%N Number of arrangements of n pseudo-circles in the affine plane with the property that every pseudo-circle intersects all the other circles.

%C Arrangements in A288559 that are connected, with the property that every pseudo-circle intersects all the other pseudo-circles.

%C These counts have 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 12 2017, based on information supplied by _Jon Wild_ on Aug 31 2016.

%E a(6) from _Manfred Scheucher_, May 09 2018