Erdős conjecture on arithmetic progressions that if the sum of the reciprocals of the members of a set of positive integers diverges, then…
Erdős conjecture on arithmetic progressions that if the sum of the reciprocals of the members of a set of positive integers diverges, then the set contains arbitrarily long arithmetic progressions.
Open the “Additive number theory” section on Wikipedia →
Source: List of unsolved problems in mathematics (CC BY-SA 4.0)