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 A319479 Lexicographically earliest sequence such that for every n and every sequence 1 <= b_1 < b_2 < ... < b_t = n, the values of barycenter((b_1, a(b_1)), (b_2, a(b_2)), ..., (b_t, a(b_t))) are distinct. 0
 1, 1, 2, 1, 4, 8, 16, 29, 51, 128, 344, 528, 1863, 5283, 12445 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The barycenter of the points {(x_1, y_1), (x_2, y_2), ..., (x_k, y_k)} is given by the average of the x and y coordinates: (Sum_{i=1..k} x_i/k, Sum_{i=1..k} y_i/k). LINKS Table of n, a(n) for n=1..15. EXAMPLE For n = 5, a(5) = 4 because letting a(5) = 1, 2, or 3 creates barycenter collisions: +-----------+----------------+--------------------------------+------------+ | candidate | set 1 | set 2 | barycenter | +-----------+----------------+--------------------------------+------------+ | (5, 1) | (1, 1); (5, 1) | (1, 1); (2, 1); (4, 1); (5, 1) | (6, 1) | | (5, 2) | (2, 1); (5, 2) | (2, 1); (3, 2); (4, 1); (5, 2) | (3.5, 1.5) | | (5, 3) | (1, 1); (5, 3) | (1, 1); (3, 2); (5, 3) | (3, 2) | +-----------+----------------+--------------------------------+------------+ And a(5) = 4 creates no such problems. CROSSREFS Cf. A285491. Sequence in context: A294104 A294061 A113820 * A303632 A133267 A145864 Adjacent sequences: A319476 A319477 A319478 * A319480 A319481 A319482 KEYWORD nonn,more AUTHOR Peter Kagey, Sep 19 2018 STATUS approved

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Last modified April 22 08:00 EDT 2024. Contains 371892 sequences. (Running on oeis4.)