On the distribution of some integers related to perfect and amicable numbers
We consider an approximation to the popular conjecture about representations of integers as sums of four squares of prime numbers.
Let denote an almost-prime with at most prime factors, counted according to multiplicity. Suppose that and are positive integers satisfying . Denote by the least almost-prime which satisfies . It is proved that for sufficiently large , there holds This result constitutes an improvement upon that of Iwaniec (1982), who obtained the same conclusion, but for the range in place of .
Let denote a positive integer with at most prime factors, counted according to multiplicity. For integers , such that , let denote the least in the arithmetic progression . It is proved that for sufficiently large , we have This result constitutes an improvement upon that of J. Li, M. Zhang and Y. Cai (2023), who obtained