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 A359970 #10 Jan 30 2023 10:32:49 %S A359970 3,10,84,433,3264,7357,37065,86441,232975,405510,1210898,1773121, %T A359970 4500787,6774404,10997356 %N A359970 Number of edges 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 A359970 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. %C A359970 See A359968 and A359969 for images of the triangle. %F A359970 a(n) = A359968(n) + A359969(n) - 1 by Euler's formula. %Y A359970 Cf. A359968 (vertices), A359969 (regions), A359971 (k-gons), A005728, A360042, A359976, A359693, A358950, A358888. %K A359970 nonn,more %O A359970 1,1 %A A359970 _Scott R. Shannon_ and _N. J. A. Sloane_, Jan 20 2023