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 A359046 #22 Dec 15 2022 06:47:58 %S A359046 1,3,7,45,66,186,267,657,721,1501,1893,2772,3654,5727,6511,9969,11340, %T A359046 14850,18051,23921,26755,35201,39975,47280,55776,69863,75385,93017, %U A359046 102864,117810,134541,161217,172921,205293,221271,252828,277242,322811,341017,393721,420702,466074,509379 %N A359046 Number of distinct regions among all circles that can be constructed on vertices of an n-sided regular polygon, using only a compass. %C A359046 See A331702 for further details. %C A359046 No formula for a(n) is currently known. %H A359046 Scott R. Shannon, <a href="/A359046/a359046.jpg">Image for n = 2</a>. In this and other images the points defining the n-sided regular polygon are show as white dots. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_1.jpg">Image for n = 3</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_2.jpg">Image for n = 4</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_3.jpg">Image for n = 5</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_4.jpg">Image for n = 6</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_5.jpg">Image for n = 7</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_6.jpg">Image for n = 8</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_7.jpg">Image for n = 9</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_8.jpg">Image for n = 10</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_9.jpg">Image for n = 11</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_10.jpg">Image for n = 12</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_11.jpg">Image for n = 18</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_12.jpg">Image for n = 21</a>. %H A359046 Scott R. Shannon, <a href="/A359046/a359046_13.jpg">Image for n = 25</a>. %F A359046 a(n) = A359047(n) - A331702(n) + 1 by Euler's formula. %Y A359046 Cf. A331702 (vertices), A359047 (edges), A359061 (k-gons), A358782, A007678. %K A359046 nonn %O A359046 1,2 %A A359046 _Scott R. Shannon_, Dec 14 2022