Problem Statement
Let $C>1$. Does the set of integers of the form $p+\lfloor C^k\rfloor$, for some prime $p$ and $k\geq 0$, have density $>0$?
Categories:
Number Theory Primes
Progress
Originally asked to Erdős by Kalmár. Erdős believed the answer is yes. Romanoff [Ro34] proved that the answer is yes if $C$ is an integer.Ding [Di25] has proved that this is true for almost all $C>1$.
Source: erdosproblems.com/244 | Last verified: January 14, 2026