OPEN
This is open, and cannot be resolved with a finite computation.
Is there a set $A\subseteq \mathbb{N}$ such that, for infinitely many $n$, all of $n-a$ are prime for all $a\in A$ with $0<a<n$ and\[\liminf\frac{\lvert A\cap [1,x]\rvert}{\pi(x)}>0?\]
Erdős and Graham could show this is true (assuming the prime $k$-tuple conjecture) if we replace $\liminf$ by $\limsup$.
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T. F. Bloom, Erdős Problem #428, https://www.erdosproblems.com/428, accessed 2026-01-16
