Let Ω(n) and ω(n) denote the number of distinct prime factors of the positive integer n, counted respectively with and without multiplicity. Let denote the Piltz function (which counts the number of ways of writing n as a product of k factors). We obtain a precise estimate of the sum for a class of multiplicative functions f, including in particular , unconditionally if 1 ≤ k ≤ 3, and under some reasonable assumptions if k ≥ 4. The result also applies to f(n) = φ(n)/n (where φ is the totient function), to (where is the sum of rth powers of divisors) and to functions related to the notion of exponential divisor. It generalizes similar results by J. Wu and Y.-K. Lau when f(n) = 1, respectively .
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-aa161-1-5, author = {Rimer Zurita}, title = {Sur un probl\`eme de R\'enyi et Ivi\'c concernant les fonctions de diviseurs de Piltz}, journal = {Acta Arithmetica}, volume = {161}, year = {2013}, pages = {69-100}, zbl = {1278.11092}, language = {fra}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-aa161-1-5} }
Rimer Zurita. Sur un problème de Rényi et Ivić concernant les fonctions de diviseurs de Piltz. Acta Arithmetica, Tome 161 (2013) pp. 69-100. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-aa161-1-5/