A285995 Number of arrangements of n circles in the affine plane such that at least two of the circles meet.

0, 0, 1, 10, 164

Offset: 0

Author

Omar E. Pol, May 17 2017

Keywords

• nonn
• bref
• hard
• more

Comments

A subset the arrangements of n circles described in A250001, which is the main entry for this sequence.

See also the comments related to A000081 from Benoit Jubin and N. J. A. Sloane in A250001.

Crossrefs

Row sums of A261070 except its column k = 0.

Cf. A000081, A250001.

Formula

a(n) = A250001(n) - A000081(n+1).