A274702 a(n) = number of arrangements of n circles in the affine plane in which all circles share part of their boundary with the boundary of the union of all the circles.

1, 2, 6, 47

Offset

1,2

Comments

Consider the arrangements of n circles described in A250001.

Links

Table of n, a(n) for n=1..4.

Crossrefs

Leading diagonal of triangle A249752.

Cf. A250001.

Sequence in context: A306784 A078537 A145502 * A072444 A334807 A052596

Adjacent sequences: A274699 A274700 A274701 * A274703 A274704 A274705

Keyword

nonn,hard,more

Author

Omar E. Pol, Jul 06 2016

Status

approved