MathDB
Problem 5 of First round

Source: VI International Festival of Young Mathematicians Sozopol, Theme for 10-12 grade

January 13, 2020
number theoryprime divisorsprime numbersDivisibility

Problem Statement

Does there exist a natural number nn with exactly 3 different prime divisors pp, qq, and rr, so that p1np-1\mid n, qr1nqr-1\mid n, q1nq-1\nmid n, r1nr-1\nmid n, and 3q+r3\nmid q+r?