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 A359253 #17 Dec 24 2022 11:05:49 %S A359253 3,14,51,116,255,466,821,1296,2003,2904,4171,5726,7795,10266,13399, %T A359253 17026,21537,26702,32995,40110,48511,57996,69121,81376,95511,111130, %U A359253 128953,148432,170595 %N A359253 Number of regions among all distinct circles that can be constructed from n equally spaced points along a line using only a compass. %C A359253 A circle is constructed for every pair of the n points, the first point defines the circle's center while the second the radius distance. The number of distinct circles constructed for n points is A001859(n-1). %C A359253 No formula for a(n) is currently known. %H A359253 Scott R. Shannon, <a href="/A359253/a359253.jpg">Image for n = 2</a>. In this and other images the n points are shown as white dots. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_1.jpg">Image for n = 3</a>. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_2.jpg">Image for n = 4</a>. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_3.jpg">Image for n = 5</a>. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_4.jpg">Image for n = 6</a>. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_5.jpg">Image for n = 10</a>. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_6.jpg">Image for n = 11</a>. %H A359253 Scott R. Shannon, <a href="/A359253/a359253_7.jpg">Image for n = 20</a>. %F A359253 a(n) = A359254(n) - A359252(n) + 1 by Euler's formula. %Y A359253 Cf. A359252 (vertices), A359254 (edges), A359258 (k-gons), A001859, A290865, A359046, A358782. %K A359253 nonn,more %O A359253 2,1 %A A359253 _Scott R. Shannon_, Dec 22 2022