%I #15 Oct 11 2024 13:57:35
%S 3,45,231,865,2081,4489,8211,14401,22857,35445,51741,74397,102271,
%T 138801,182739,238181,303175,383097,474995,586021,712003,860829,
%U 1028225,1223773,1440593,1689993,1965525,2279509,2622993,3011405,3433615,3907241,4419261,4988781,5603271
%N Number of regions among all distinct circles that can be constructed from a 2 X n square grid of points using only a compass.
%C See A359859 for further details. No formula for a(n) is known.
%H Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/A359859%2B60%2B61.py">Python program</a>.
%H Scott R. Shannon, <a href="/A359860/a359860.jpg">Image for n = 1</a>.
%H Scott R. Shannon, <a href="/A359860/a359860_1.jpg">Image for n = 2</a>.
%H Scott R. Shannon, <a href="/A359860/a359860_2.jpg">Image for n = 3</a>.
%H Scott R. Shannon, <a href="/A359860/a359860_3.jpg">Image for n = 4</a>.
%H Scott R. Shannon, <a href="/A359860/a359860_4.jpg">Image for n = 5</a>.
%H Scott R. Shannon, <a href="/A359860/a359860_5.jpg">Image for n = 8</a>.
%F a(n) = A359861(n) - A359859(n) + 1 by Euler's formula.
%Y Cf. A359859 (vertices), A359861 (edges), A359862 (k-gons), A001859, A359253.
%K nonn
%O 1,1
%A _Scott R. Shannon_, Jan 16 2023
%E a(19)-a(35) from _Lucas A. Brown_, Oct 11 2024