number theoryrelatively primenumber theory unsolved
Problem Statement
Define a finite set A to be 'good' if it satisfies the following conditions:* For every three disjoint element of A, like a,b,c we have gcd(a,b,c)=1;* For every two distinct b,c∈A, there exists an a∈A, distinct from b,c such that bc is divisible by a.Find all good sets.