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 A372614 #21 May 13 2024 09:14:20 %S A372614 6,87,481,1992,6969,15409,35202,58422,107677,159138,268572,350860, %T A372614 557049 %N A372614 Number of vertices 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, using only a compass. %C A372614 A circle is constructed for every pair of the 3 + 3*n points, the first point defines the circle's center while the second the radius distance. %H A372614 Scott R. Shannon, <a href="/A372614/a372614_13.jpg">Image for n = 0</a>. In this and other images the 3 + 3*n vertices forming the triangle are drawn larger for clarity. %H A372614 Scott R. Shannon, <a href="/A372614/a372614_14.jpg">Image for n = 1</a>. %H A372614 Scott R. Shannon, <a href="/A372614/a372614_15.jpg">Image for n = 2</a>. %H A372614 Scott R. Shannon, <a href="/A372614/a372614_16.jpg">Image for n = 3</a>. %H A372614 Scott R. Shannon, <a href="/A372614/a372614_17.jpg">Image for n = 4</a>. %F A372614 a(n) = A372616(n) - A372615(n) + 1 by Euler's formula. %Y A372614 Cf. A372615 (regions), A372616 (edges), A372617 (k-gons), A372682 (number of circles), A372731, A371373, A354605, A360351. %K A372614 nonn,more %O A372614 0,1 %A A372614 _Scott R. Shannon_, May 07 2024