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 A359692 #11 Feb 16 2025 08:34:04 %S A359692 2,12,94,382,2486,4946,24100,53152,138158,233254,700720,999364, %T A359692 2559344,3785044,6027148,9210820 %N A359692 Number of regions in a regular drawing of a complete bipartite graph where the vertex positions on each part equal the Farey series of order n. %C A359692 The number of vertices along each edge is A005728(n). No formula for a(n) is known. %H A359692 Scott R. Shannon, <a href="/A359692/a359692.jpg">Image for n = 1</a>. %H A359692 Scott R. Shannon, <a href="/A359692/a359692_1.jpg">Image for n = 2</a>. %H A359692 Scott R. Shannon, <a href="/A359692/a359692_2.jpg">Image for n = 3</a>. %H A359692 Scott R. Shannon, <a href="/A359692/a359692_3.jpg">Image for n = 4</a>. %H A359692 Scott R. Shannon, <a href="/A359692/a359692_4.jpg">Image for n = 5</a>. %H A359692 Scott R. Shannon, <a href="/A359692/a359692_5.jpg">Image for n = 6</a>. %H A359692 Scott R. Shannon, <a href="/A359692/a359692_6.jpg">Image for n = 7</a>. %H A359692 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CompleteBipartiteGraph.html">Complete Bipartite Graph</a>. %H A359692 Wikipedia, <a href="https://en.wikipedia.org/wiki/Farey_sequence">Farey sequence</a>. %F A359692 a(n) = A359693(n) - A359690(n) + 1 by Euler's formula. %Y A359692 Cf. A359690 (vertices), A359691 (crossings), A359693 (edges), A359694 (k-gons), A005728, A290131, A359653, A358886, A358882, A006842, A006843. %K A359692 nonn %O A359692 1,1 %A A359692 _Scott R. Shannon_ and _N. J. A. Sloane_, Jan 11 2023