In general Sieve of Sundaram , produces primes smaller than ( 2 * x + 2 ) for a number given number x . Since we want primes smaller than MAX , we reduce MAX to half . This array is used to separate numbers of the form i + j + 2 ij from others where 1 <= i <= j
marked = [ False ] * int ( MAX / 2 + 1 ) ; NEW_LINE