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 A333354 Minimum cost of path that starts at 1 and visits integers from 1 to n, inclusive, each at least once, where the cost to travel from a to b is LCM(a, b). 0
 0, 2, 7, 12, 21, 28, 40, 51, 65, 79, 100, 114, 138, 158, 182, 205, 238, 259, 295, 324, 358, 390, 435, 463, 511, 549, 593, 634 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS A. Catanzaro, J. Feldman, M. Higgins, B. Kimball, H. Kirk, A. C Maravelias, and D. Sinha, LCM Optimal Paths, Girls' Angle Bulletin, Vol. 13, No. 4 (2020), 13-19. EXAMPLE For n = 3, the optimal path is 1, 2, 1, 3, which has cost 2 + 2 + 3 = 7. For n = 4, the optimal path is 1, 3, 1, 2, 4, which has cost 3 + 3 + 2 + 4 = 12. For n = 7, there are multiple optimal paths of which 1, 3, 6, 2, 4, 1, 5, 1, 7 is one and has cost 3 + 6 + 6 + 4 + 4 + 5 + 5 + 7 = 40. For n = 20, an optimal path is 1, 11, 1, 13, 1, 17, 1, 19, 1, 7, 14, 2, 16, 8, 4, 12, 6, 18, 9, 3, 15, 5, 10, 20. CROSSREFS Sequence in context: A023669 A137401 A309150 * A119713 A213041 A293330 Adjacent sequences:  A333351 A333352 A333353 * A333355 A333356 A333357 KEYWORD nonn,hard,more AUTHOR Richard S. Chang, May 04 2020 EXTENSIONS a(21)-a(28) from Bert Dobbelaere, Aug 22 2020 STATUS approved

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Last modified June 22 14:15 EDT 2021. Contains 345380 sequences. (Running on oeis4.)