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%I #14 Jan 30 2023 10:33:52
%S 3,10,55,202,902,1868,5886,11676,24322,39440,84155,120151,228121,
%T 324856,474396,670552,1104433,1402237,2185044,2761367,3654893,4628608,
%U 6706612,8005739,10770733
%N 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 on one edge equal the Farey series of order n while on the other they divide its length into n equal segments.
%C The number of vertices on the edge with point positions equaling the Farey series of order n is A005728(n). No formula for a(n) is known.
%C See A359974 and A359975 for images of the triangle.
%C This graph is related to the 'Farey fan' given in the reference.
%D McIlroy, M. D. "A Note on Discrete Representation of Lines". AT&T Technical Journal, 64 (1985), 481-490.
%F a(n) = A359974(n) + A359975(n) - 1 by Euler's formula.
%Y Cf. A359974 (vertices), A359975 (regions), A359977 (k-gons), A005728, A359970, A359693, A358950, A358888.
%K nonn,more
%O 1,1
%A _Scott R. Shannon_ and _N. J. A. Sloane_, Jan 20 2023
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