let max = 1000 in
let primes = Array.create 1000 true in
let num = 2 in
let outer_func num =
 if num == sqrt.max then num  
 else if primes.(num) == true then
    let pos = num * num in
    let inner_func pos =
       if pos > max then pos
       else (
          primes.(pos)<-false;);
       inner_func (pos + num);
  outer_func (num + 1);
for counter = 2 to max do
  if primes.(counter) == true then
     print_line counter;
done;;