OFFSET

1,3

LINKS

David Applegate, Table of n, a(n) for n = 1..100

N. J. A. Sloane (in collaboration with Scott R. Shannon), Art and Sequences, Slides of guest lecture in Math 640, Rutgers Univ., Feb 8, 2020. Mentions this sequence.

EXAMPLE

With 3 points, there are 3 semicircles above the baseline, which bound a(3) = 3 regions. With 4 points, there are 6 semicircles, defining 7 regions (use the Halser webpage with n = 3 and 4). - N. J. A. Sloane, Aug 12 2017

CROSSREFS

KEYWORD

nonn

AUTHOR

David Applegate, Aug 12 2017

STATUS

approved