MathDB
2019 T11: Subset of Natural Numbers Satisfying Inclusion Property

Source:

January 27, 2019
2019team

Problem Statement

Let SS be a subset of the natural numbers such that 0∈S0\in S, and for all n∈Nn\in\mathbb N, if nn is in SS, then both 2n+12n+1 and 3n+23n+2 are in SS. What is the smallest number of elements SS can have in the range {0,1,…,2019}\{0,1,\ldots, 2019\}?
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