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Is it true that for every $k$ there exists $n$ such that\[\prod_{0\leq i\leq k}(n-i) \mid \binom{2n}{n}?\]
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Erdős and Graham write that $n+1$ always divides $\binom{2n}{n}$ (indeed $\frac{1}{n+1}\binom{2n}{n}$ is the $n$th Catalan number), but it is quite rare that $n$ divides $\binom{2n}{n}$.

Pomerance [Po14] has shown that for any $k\geq 0$ there are infinitely many $n$ such that $n-k\mid\binom{2n}{n}$, although the set of such $n$ has upper density $<1/3$. Pomerance also shows that the set of $n$ such that\[\prod_{1\leq i\leq k}(n+i)\mid \binom{2n}{n}\]has density $1$.

The smallest $n$ for each $k$ are listed as A375077 on the OEIS.

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Formalised statement? Yes
Related OEIS sequences: A375077
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Additional thanks to: Ralf Stephan

When referring to this problem, please use the original sources of Erdős. If you wish to acknowledge this website, the recommended citation format is:

T. F. Bloom, Erdős Problem #396, https://www.erdosproblems.com/396, accessed 2026-01-14