Problem 424

Erdős Problem #424: declared status 'open'. Formalized: yes. Let $a_1=2$ and $a_2=3$ and continue the sequence by appending to $a_1,\ldots,a_n$ all possible values of $a_ia_j-1$ with $i\neq j$. Is it true that the set of integers which eventually appear has positive density? Prize: no. OEIS: A005244. Tags: number theory.