We are often interested in the divisors of a number, \(n\),
function divisors(n::Int)
n == one(n) && return [one(n)]
ds = [ 1, n ]
i = 2
while i ≤ sqrt(n)
if n % i == 0
if i != div(n, i)
ds = vcat(ds, [i, div(n, i)])
else
ds = vcat(ds, [i])
end
end
i += 1
end
return sort(ds)
end