Gausstotientit.jl

# totientit 1...n using Gauss divisor sum property
# idea https://cp-algorithms.com/algebra/phi-function.html
# Juhani Kaukoranta 4.4.2021
# Julia-ohjelma Gausstotientit.jl
function Gausstotientit(n)
    phi =Vector{Int64}(undef,n)
    phi[1]=1
    phi[2]=1
    for i = 2:n
        phi[i] = i-1
    end
    for i = 2:n
        for j = 2*i : i : n
            phi[j] -= phi[i]
        end
    end
    return phi
end