This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A373107 #7 May 26 2024 08:20:27 %S A373107 12,136,932,3252,9144,20032,41260,71832,121460,188656,291488 %N A373107 Number of regions among all distinct circles that can be constructed from the 4 vertices and the equally spaced 4*n points placed on the sides of a square when every pair of the 4 + 4*n points are connected by a circle and where the points lie at the ends of the circle's diameter. %C A373107 A circle is constructed for every pair of the 4 + 4*n points, the two points lying at the ends of a diameter of the circle. %H A373107 Scott R. Shannon, <a href="/A373107/a373107.jpg">Image for n = 0</a>. In this and other images the 4 + 4*n vertices forming the square are drawn as white dots for clarity. %H A373107 Scott R. Shannon, <a href="/A373107/a373107_1.jpg">Image for n = 1</a>. %H A373107 Scott R. Shannon, <a href="/A373107/a373107_2.jpg">Image for n = 2</a>. %H A373107 Scott R. Shannon, <a href="/A373107/a373107_3.jpg">Image for n = 3</a>. %H A373107 Scott R. Shannon, <a href="/A373107/a373107_4.jpg">Image for n = 7</a>. %F A373107 a(n) = A373108(n) - A373106(n) + 1 by Euler's formula. %Y A373107 Cf. A373106 (vertices), A373108 (edges), A373109 (k-gons), A373110 (circles), A372978, A372732, A358782, A362234, A360352. %K A373107 nonn,more %O A373107 0,1 %A A373107 _Scott R. Shannon_, May 25 2024