Moebius Mu Function

Returns the corresponding Moebius mu value of an input value.

The Moebius mu function is used in number theory and combinatorics. It was first introduced by August Ferdinand Moebius in 1831. The function is denoted by the Greek lowercase letter mu(n). mu(n) is defined for all strictly positive natural numbers n and returns values in {-1,0,1}.
The function is multiplicative, i.e. mu(ab) = mu(a)mu(b) when a and b are coprime.