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 A360350 Number of distinct circles that can be constructed from an n X n square grid of points when each pair of points is connected by a circle and the points lie at the ends of a diameter of the circle. 8
 5, 26, 79, 185, 366, 653, 1077, 1678, 2494, 3571, 4959, 6718, 8889, 11541, 14740, 18553, 23027, 28278, 34351, 41352, 49356, 58454, 68732, 80330, 93304, 107757, 123815, 141605, 161211, 182795, 206393, 232190, 260331, 290907, 324090, 360080, 398856, 440655, 485655 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS A circle is constructed for every pair of points on the n X n grid, the points lying at the ends of a diameter of the circle. No formula for a(n) is known. See A360351 and A360352 for images of the resulting vertices and regions. LINKS Table of n, a(n) for n=2..40. N. J. A. Sloane, New Gilbreath Conjectures, Sum and Erase, Dissecting Polygons, and Other New Sequences, Doron Zeilberger's Exper. Math. Seminar, Rutgers, Sep 14 2023: Video, Slides, Updates. (Mentions this sequence.) PROG (PARI) a(n) = { my (p = vector(n^2, k, (k-1)%n + ((k-1)\n)*I)); #setbinop((i, j)->[i+j, norm(i-j)], p)-n^2; } \\ Rémy Sigrist, Sep 24 2023 CROSSREFS Cf. A360351 (vertices), A360352 (regions), A360353 (edges), A360354 (k-gons), A359931. Sequence in context: A081886 A081530 A254831 * A145013 A096943 A166810 Adjacent sequences: A360347 A360348 A360349 * A360351 A360352 A360353 KEYWORD nonn AUTHOR Scott R. Shannon, Feb 03 2023 EXTENSIONS More terms from Rémy Sigrist, Sep 24 2023 STATUS approved

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Last modified July 22 12:38 EDT 2024. Contains 374499 sequences. (Running on oeis4.)