Erdős Problem 488 #
Reference: erdosproblems.com/488
Let $A$ be a finite set and $$B = \{n \ge 1 : a \nmid n \text{ for all } a \in A\}.$$ Is it true that, for every $m > n \ge \max(A)$, $$\frac{|B \cap [1, m]|}{m} < 2 \frac{|B \cap [1, n]|}{n}?$$
Reference: erdosproblems.com/488
Let $A$ be a finite set and $$B = \{n \ge 1 : a \nmid n \text{ for all } a \in A\}.$$ Is it true that, for every $m > n \ge \max(A)$, $$\frac{|B \cap [1, m]|}{m} < 2 \frac{|B \cap [1, n]|}{n}?$$