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 A372978 #7 May 19 2024 08:53:45 %S A372978 45,628,4633,15476,41561,98808,206317,333272,590181 %N A372978 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, using only a compass. %C A372978 A circle is constructed for every pair of the 4 + 4*n points, the first point defines the circle's center while the second the radius distance. %H A372978 Scott R. Shannon, <a href="/A372978/a372978.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 A372978 Scott R. Shannon, <a href="/A372978/a372978_1.jpg">Image for n = 1</a>. %H A372978 Scott R. Shannon, <a href="/A372978/a372978_2.jpg">Image for n = 2</a>. %H A372978 Scott R. Shannon, <a href="/A372978/a372978_3.jpg">Image for n = 3</a>. %F A372978 a(n) = A372979(n) - A372977(n) + 1 by Euler's formula. %Y A372978 Cf. A372977 (vertices), A372979 (edges), A372980 (k-gons), A372981 (circles), A372615, A371374, A353782, A360352. %K A372978 nonn,more %O A372978 0,1 %A A372978 _Scott R. Shannon_, May 19 2024