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Erdős problem 650

Let f(m)f(m) be such that if A⊆{1,…,N}A\subseteq \{1,\ldots,N\} has ∣A∣=m\lvert A\rvert=m then every interval in [1,∞)[1,\infty) of length 2N2N contains ≥f(m)\geq f(m) many distinct integers b1,…,brb_1,\ldots,b_r where each bib_i is divisible by some ai∈Aa_i\in A, where a1,…,ara_1,\ldots,a_r are distinct.

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4 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

650.lean

Retained formal statement3 of 4

Erdős and Selfridge proved (see [Er78] and [Er86c]) that f(m2)≤2mf(m^2)\leq 2m, which implies f(m)≤2⌈m⌉f(m)\leq 2\lceil \sqrt{m}\rceil for all mm.

FormalConjectures/ErdosProblems/650.leanErdos650.erdos_650.variants.erdos_selfridge1 lineExact file
∀ (m : ℕ), Erdos650.f (m ^ 2) ≤ 2 * m
SolvedStatement only, no proof