Dear readers! Let a(n) = Product_{k=1..n} (prime(k+1)+prime(k))/(prime(k+1)-prime(k)). Conjecture: a(n) is an integer for every natural n. Is it known or provable? Best regards, Thomas Ordowski <#m_-7681193058414376069_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>