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 A359117 #14 May 06 2025 11:26:06 %S A359117 1,2,8,30,250,548,3180,7468,20684,36164,112406,163600,425144,636208, %T A359117 1028934,1581766,3323182,4249976,8216442,10668790,15329216 %N A359117 Number of regions in the planar Farey Ring graph FR(n) defined in A359116, including the regions between the convex hull and the bounding circle. %H A359117 Scott R. Shannon, <a href="/A359117/a359117.jpg">Image for n = 3</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_1.jpg">Image for n = 4</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_2.jpg">Image for n = 5</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_3.jpg">Image for n = 6</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_4.jpg">Image for n = 7</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_5.jpg">Image for n = 8</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_6.jpg">Image for n = 9</a>. %H A359117 Scott R. Shannon, <a href="/A359117/a359117_7.jpg">Image for n = 10</a>. %F A359117 a(n) = A359118 - A359116 + 1 by Euler's formula. %Y A359117 Cf. A359116 (vertices), A359118 (edges), A359119 (k-gons), A358886, A006842, A006843, A005728, A007678. %K A359117 nonn,more %O A359117 1,2 %A A359117 _Scott R. Shannon_ and _N. J. A. Sloane_, Dec 17 2022