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Maximum Divisibility-Chain Subset Size

1925SpecialistCombinatoricsNumber Theory

SMO Finalrunde

Let $M \subset \{1,2,3, \ldots, 2007\}$ be a set with the following property: Among any three numbers from $M$, one can always choose two such that one is divisible by the other. What is the maximum possible number of elements in $M$?
0 students attempted0% solvedRating 1925

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