title: Write an algorithm to return the prime numbers of an integer, for example if your input is 10 the output is list a with elements 2 and 5
body: <p>this one i get as assignment in discrete maths.
  i try to do like this.</p>
  
  <pre><code>procedure prime_numbers (x)
    n:= 1
    for i:= to n&lt;=x do
      n mod i=1 then
        return (prime)
  end prime_number.
  </code></pre>