Product of three primes in large arithmetic progressions

Ramachandran Balasubramanian, Olivier Ramaré, Priyamvad Srivastav

For any $\epsilon >0$, there exists $q_0(\epsilon )$ such for any $q\ge q_0(\epsilon )$ and any invertible residue class $a$ modulo $q$, there exists a natural number that is congruent to $a$ modulo $q$ a…