Skip to content

Erdős problem 442

Let Logx:=max{logx,1}\operatorname{Log} x := \max\{\log x, 1\}, Log2x=Log(Logx)\operatorname{Log}_2x = \operatorname{Log} (\operatorname{Log} x), and Log3x=Log(Log(Logx)).\operatorname{Log}_3x = \operatorname{Log}(\operatorname{Log}(\operatorname{Log} x)). Is it true that if ANA\subseteq\mathbb{N} is such that 1Log2xnA:nx1n \frac{1}{\operatorname{Log}_2 x} \sum_{n\in A: n\leq x} \frac{1}{n}\to\infty then (nA:nx1n)2n,mA:n<mx1lcm(n,m) \left(\sum_{n\in A: n\leq x} \frac{1}{n}\right)^2 \sum_{n, m \in A: n < m \leq x} \frac{1}{\operatorname{lcm}(n, m)}\to\infty as xx\to\infty?

Workspace

Open this exact Problem, source revision, and authority Repository in Workbench. This handoff does not clone, switch, upload, or execute anything.

Canvas

public preview
  1. Source#442
  2. ResultNone
  3. Checks0

Search problems.science

Find a Problem, Result, source, or page