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3

Part of 1998 Portugal MO

Problems(1)

2000 -element subset of 1-3000 where none of them is twice another

Source: Portugal OPM 1998 p3

5/18/2024
Could the set {1,2,3,...,3000}\{1,2,3,...,3000\} contain a subset of 20002000 elements such that none of them is twice the size of another?
combinatorics