### What is the value of mu zero?

So I believe you are asking about the Moebius or Möbius Mu(n) function. This is a number theoretic function defined as follows: Mu(n) = 0 if n has one or more repeated prime factors Mu(n) = 1 if n = 1 Mu(n) = (−1)^k if n is the product of k distinct primes Mu(n) = Mu(−n), (Mu(n) is not normally defined for n < 1) Mu(0) = 0 So the answer to your question is…