On the number of integers ≤ x whose prime factors divide n

If n nd x re positive integers, then we letf(n, x) denote the number mentioned in the title, i.e., the number of integers m with 1 <= m <= x, (The notation m n means that m divides some power of n, or in other words, that all prime factors of m divide n.) P. ErdSs conjectured (in a letter to the author, December 2, 1960) that the average M(x) x-i=1 f(n, x) can be written as M(x) x-iF(x) exp((log x)l2+()), where (x) --, 0 for x ---,