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Problem #961: Let $f(k)$ be the minimal $n$ such that every set of $n$...

Let $f(k)$ be the minimal $n$ such that every set of $n$ consecutive integers $>k$ contains an integer divisible by a prime $>k$. Estimate $f(k)$.

Problem Statement

Let $f(k)$ be the minimal $n$ such that every set of $n$ consecutive integers $>k$ contains an integer divisible by a prime $>k$. Estimate $f(k)$.
Categories: Number Theory

Progress

In other words, how large can a consecutive set of $k$-smooth integers be? Sylvester and Schur (see [Er34]) proved $f(k)\leq k$ and Erdős [Er55d] proved\[f(k)<3\frac{k}{\log k}.\]Jutila [Ju74] and Ramachandra, and Shorey [RaSh73] proved\[f(k) \ll \frac{\log\log\log k}{\log \log k}\frac{k}{\log k}.\]It is likely that $f(k) \ll (\log k)^{O(1)}$.

This is essentially equivalent to [683].

Source: erdosproblems.com/961 | Last verified: January 19, 2026

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