On a pair of zeta functions

Abstract

Let $m$ be a positive integer, and define $$ζ_m(s)=\sum_{n=1}^\infty\frac{(-e^{2πi/m})^{ω(n)}}{n^s}\ \ \ \ \text{and} \ \ \ \ ζ^*_m(s)=\sum_{n=1}^\infty\frac{(-e^{2πi/m})^{Ω(n)}}{n^s},$$ for $\Re(s)>1$, where $ω(n)$ denotes the number of distinct prime factors of $n$, and $Ω(n)$ represents the total number of prime factors of $n$ (counted with multiplicity). In this paper we study these two zeta functions and related arithmetical functions. We show that $$\sum^\infty_{n=1\atop n\ \text{is squarefree}}\frac{(-e^{2πi/m})^{ω(n)}}n=0\quad\text{if}\ \ m>4,$$ which is similar to the known identity $\sum_{n=1}^\inftyμ(n)/n=0$ equivalent to the Prime Number Theorem. For $m>4$, we prove that $$ζ_m(1):=\sum_{n=1}^\infty\frac{(-e^{2πi/m})^{ω(n)}}n=0 \ \ \ \ \text{and}\ \ \ \ ζ^*_m(1):=\sum_{n=1}^\infty\frac{(-e^{2πi/m})^{Ω(n)}}n=0.$$ We also raise a hypothesis on the parities of $Ω(n)-n$ which implies the Riemann Hypothesis.