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 A372732 #8 May 12 2024 10:04:45 %S A372732 7,88,438,1567,3910,9504,17905,32833,54066,86365,128380,190152,262699, %T A372732 365761,486711,642154 %N A372732 Number of regions among all distinct circles that can be constructed from the 3 vertices and the equally spaced 3*n points placed on the sides of an equilateral triangle when every pair of the 3 + 3*n points are connected by a circle and where the points lie at the ends of the circle's diameter. %C A372732 A circle is constructed for every pair of the 3 + 3*n points, the two points lying at the ends of a diameter of the circle. %H A372732 Scott R. Shannon, <a href="/A372732/a372732.jpg">Image for n = 0</a>. %H A372732 Scott R. Shannon, <a href="/A372732/a372732_1.jpg">Image for n = 1</a>. %H A372732 Scott R. Shannon, <a href="/A372732/a372732_2.jpg">Image for n = 2</a>. %H A372732 Scott R. Shannon, <a href="/A372732/a372732_3.jpg">Image for n = 3</a>. %H A372732 Scott R. Shannon, <a href="/A372732/a372732_4.jpg">Image for n = 4</a>. %F A372732 a(n) = A372733(n) - A372731(n) + 1 by Euler's formula. %Y A372732 Cf. A372731 (vertices), A372733 (edges), A372734 (k-gons), A372735 (number of circles), A372615, A371374, A353782, A360352. %K A372732 nonn,more %O A372732 0,1 %A A372732 _Scott R. Shannon_, May 12 2024