Properties of non powerful numbers.
The Selberg sieve provides majorants for certain arithmetic sequences, such as the primes and the twin primes. We prove an – restriction theorem for majorants of this type. An immediate application is to the estimation of exponential sums over prime -tuples. Let and be positive integers. Write , where is the set of all such that the numbers are all prime. We obtain upper bounds for , , which are (conditionally on the Hardy-Littlewood prime tuple conjecture) of the correct order...