A285995 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

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.

LINKS

FORMULA

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

CROSSREFS

Row sums of A261070 except its column k = 0.

KEYWORD

nonn,bref,hard,more

AUTHOR

Omar E. Pol, May 17 2017

STATUS

approved