The classical Möbius function: μ(n) is an important multiplicative function in number theory and combinatorics.

There are several ways to implement a Möbius function.

A fairly straightforward method is to find the prime factors of a positive integer n, then define μ(n) based on the sum of the primitive factors. It has the values {−1, 0, 1} depending on the factorization of n:

 μ(1) is defined to be 1.
 μ(n) = 1 if n is a square-free positive integer with an even number of prime factors.
 μ(n) = −1 if n is a square-free positive integer with an odd number of prime factors.
 μ(n) = 0 if n has a squared prime factor.


Task

 Write a routine (function, procedure, whatever) μ(n) to find the Möbius number for a positive integer n.
 Use that routine to find and display here, on this page, at least the first 99 terms in a grid layout. (Not just one long line or column of numbers.)


See also

 Wikipedia: Möbius function


Related Tasks

 Mertens function


 
// Möbius function. Nigel Galloway: January 31st., 2021
let fN g=let n=primes32()
         let rec fN i g e l=match (l/g,l%g,e) with (1,0,false)->i
                                                  |(n,0,false)->fN (0-i) g true n
                                                  |(_,0,true) ->0
                                                  |_          ->fN i (Seq.head n) false l
         fN -1 (Seq.head n) false g
let mobius=seq{yield 1; yield! Seq.initInfinite((+)2>>fN)}
mobius|>Seq.take 500|>Seq.chunkBySize 25|>Seq.iter(fun n->Array.iter(printf "%3d") n;printfn "")
 