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 A359968 #14 Jan 30 2023 10:32:29 %S A359968 3,6,37,195,1467,3408,17113,40435,109638,191718,572939,842487,2139708, %T A359968 3231583,5261013 %N A359968 Number of vertices formed inside a right triangle by the straight line segments mutually connecting all vertices and points on the two shorter edges whose positions equal the Farey series of order n. %C A359968 The number of vertices along the shorter edges is A005728(n). No formula for a(n) is known. The sequence is inspired by the Farey fan; see A360042. %H A359968 Scott R. Shannon, <a href="/A359968/a359968.png">Image for n = 2</a>. %H A359968 Scott R. Shannon, <a href="/A359968/a359968_1.png">Image for n = 3</a>. %H A359968 Scott R. Shannon, <a href="/A359968/a359968_2.png">Image for n = 4</a>. %H A359968 Scott R. Shannon, <a href="/A359968/a359968_3.png">Image for n = 5</a>. %H A359968 Scott R. Shannon, <a href="/A359968/a359968_4.png">Image for n = 6</a>. %F A359968 a(n) = A359970(n) - A359969(n) + 1 by Euler's formula. %Y A359968 Cf. A359969 (regions), A359970 (edges), A359971 (k-gons), A005728, A360042, A359974, A359690, A358949, A358887. %K A359968 nonn,more %O A359968 1,1 %A A359968 _Scott R. Shannon_ and _N. J. A. Sloane_, Jan 20 2023