A288562 Number of arrangements of n pseudo-circles in the affine plane with the property that every pseudo-circle intersects all the other circles.

1, 1, 1, 4, 45, 5108, 4598809

Offset

0,4

Comments

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

These counts have been reduced for mirror symmetry.

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

Links

Table of n, a(n) for n=0..6.

Crossrefs

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

Sequence in context: A132552 A189273 A288554 * A349866 A222899 A119729

Adjacent sequences: A288559 A288560 A288561 * A288563 A288564 A288565

Keyword

nonn,more

Author

N. J. A. Sloane, Jun 12 2017, based on information supplied by Jon Wild on Aug 31 2016.

Extensions

a(6) from Manfred Scheucher, May 09 2018

Status

approved