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A331425
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Divide each side of a triangle into 2*n (n>=1) equal parts and trace the corresponding cevians, i.e., join every point, except for the first and last ones, with the opposite vertex. a(n) is the number of points at which three cevians meet.
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2
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1, 7, 13, 19, 25, 31, 37, 43, 49, 61, 61, 91, 73, 79, 91, 91, 97, 103, 109, 133, 133, 127, 133, 187, 145, 151, 157, 175, 169, 235, 181, 187, 205, 199, 229, 283, 217, 223, 235, 325, 241, 283, 253, 271, 331, 271, 277, 343, 289, 301, 301, 319, 313, 319, 349, 439
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OFFSET
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1,2
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COMMENTS
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A bisection of A331423.
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LINKS
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Table of n, a(n) for n=1..56.
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FORMULA
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a(n) = A331423(2*n).
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MATHEMATICA
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CevIntersections[n_] := Length[Solve[(n - i)*(n - j)*(n - k) - i*j*k == 0 && 0 < i < n && 0 < j < n && 0 < k < n, {i, j, k}, Integers]];
Map[CevIntersections[#] &, Range[2, 50, 2]]
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CROSSREFS
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Cf. A331423, A331428.
Sequence in context: A070419 A080199 A016921 * A260682 A184521 A123843
Adjacent sequences: A331422 A331423 A331424 * A331426 A331427 A331428
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KEYWORD
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nonn
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AUTHOR
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César Eliud Lozada, Jan 16 2020
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STATUS
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approved
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