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Search: id:A064796
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| A064796 |
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Largest integer m such that every permutation (p_1, ..., p_n) of (1, ..., n) satisfies p_i * p_{i+1} >= m for some i, 1 <= i <= n, where p_{n+1} = p_1. |
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+0
5
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| 1, 2, 6, 8, 12, 15, 20, 24, 30, 35, 42, 48, 56, 63, 72, 80, 90, 99, 110, 120, 132, 143, 156, 168, 182, 195, 210, 224, 240, 255, 272, 288, 306, 323, 342, 360, 380, 399, 420, 440, 462, 483, 506, 528, 552, 575, 600, 624, 650, 675, 702, 728, 756, 783, 812, 840, 870
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Conjecture: a(n) = (n+1)(n+3)/4 for odd n, a(n) = (n)(n+4)/4 for even n. - Jud McCranie (j.mccranie(AT)comcast.net), Oct 25 2001
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FORMULA
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For odd n > 2, a(n) = (n+1)(n+3)/4. For even n > 2, a(n) = n(n+4)/4. - David Wasserman (wasserma(AT)spawar.navy.mil), Aug 19 2002
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EXAMPLE
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n=5: we must arrange the numbers 1..5 in a circle so that the max of the products of pairs of adjacent terms is minimized. The answer is 15243, with max product = 12, so a(5) = 12.
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CROSSREFS
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Cf. A064764, A035106, A064797.
Sequence in context: A153880 A120227 A138626 this_sequence A083769 A057656 A084724
Adjacent sequences: A064793 A064794 A064795 this_sequence A064797 A064798 A064799
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Oct 21 2001
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EXTENSIONS
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More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com) and Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 22 2001
More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Aug 19 2002
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