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Let $\omega(n)$ count the number of distinct prime factors of $n$. What is the size of the largest interval $I\subseteq [x,2x]$ such that $\omega(n)>\log\log n$ for all $n\in I$?
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Erdős [Er37] proved that the density of integers $n$ with $\omega(n)>\log\log n$ is $1/2$. The Chinese remainder theorem implies that there is such an interval with\[\lvert I\rvert \geq (1+o(1))\frac{\log x}{(\log\log x)^2}.\]It could be true that there is such an interval of length $(\log x)^{k}$ for arbitrarily large $k$.

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This page was last edited 28 October 2025.

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T. F. Bloom, Erdős Problem #452, https://www.erdosproblems.com/452, accessed 2026-01-16