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 A064764 Largest integer m such that every permutation (p_1, ..., p_n) of (1, ..., n) satisfies lcm(p_i, p_{i+1}) >= m for some i, 1 <= i <= n-1. 6
 1, 2, 3, 4, 6, 6, 12, 12, 12, 12, 18, 18, 24, 24, 24, 24, 35, 35, 44, 44, 44, 44, 55, 55, 55, 55, 55, 55, 68, 68, 85, 85, 85, 85, 85, 85, 102, 102, 102, 102, 119, 119, 145, 145, 145, 145, 174, 174, 174, 174, 174, 174, 203, 203, 203, 203, 203, 203, 232, 232, 261, 261, 261 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For n >= 4, a(n) >= A073818(pi(n)), with equality for 19 <= n <= 70. - David Wasserman, Aug 17 2002 LINKS P. Erdős, R. Freud, and N. Hegyvári, Arithmetical properties of permutations of integers, Acta Mathematica Hungarica 41:1-2 (1983), pp 169-176. D. Wasserman, Proof of terms 11-70 FORMULA a(n) = (1+o(1))n^2/(4 log n) as n -> infinity. EXAMPLE n=6: we must arrange the numbers 1..6 so that the max of the lcm of pairs of adjacent terms is minimized. The answer is 632415, with max lcm = 6, so a(6) = 6. CROSSREFS Cf. A035106, A064736, A064796, A064797, A000720, A073818. Sequence in context: A007464 A210733 A265564 * A123131 A206398 A000793 Adjacent sequences:  A064761 A064762 A064763 * A064765 A064766 A064767 KEYWORD nonn,nice AUTHOR N. J. A. Sloane, Oct 21 2001 EXTENSIONS More terms from Vladeta Jovovic, Oct 21 2001 Further terms from David Wasserman, Aug 17 2002 STATUS approved

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Last modified October 22 22:34 EDT 2019. Contains 328335 sequences. (Running on oeis4.)