"The twin prime conjecture, that n and n+2 are infinitely often primes simultaneously, is probably the oldest unsolved problem in mathematics. De Polignac (1849) conjectured that for every even value of h, n and n+h are infinitely often primes simultaneously. These are the most basic problems on gaps and patterns in primes. Another one is the conjecture of Waring (1770), stating that there are ar ...