A359693 - OEIS

%I #8 Jan 12 2023 16:13:50

%S 6,24,162,670,4456,8942,44470,98902,259114,438552,1330566,1897164,

%T 4893752,7246502,11544278,17678880

%N Number of edges in a regular drawing of a complete bipartite graph where the vertex positions on each part equal the Farey series of order n.

%C The number of vertices along each edge is A005728(n). No formula for a(n) is known.

%C See A359690 and A359692 for images of the graph.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CompleteBipartiteGraph.html">Complete Bipartite Graph</a>.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Farey_sequence">Farey sequence</a>.

%F a(n) = A359690(n) + A359692(n) - 2*A005728(n) + 1 by Euler's formula.

%Y Cf. A359690 (vertices), A359691 (crossings), A359692 (regions), A359694 (k-gons), A005728, A290132, A359655, A358888, A358884, A006842, A006843.

%K nonn,more

%O 1,1

%A _Scott R. Shannon_ and _N. J. A. Sloane_, Jan 11 2023