improved memory usage

inf2440/hw2/Sieve.java

@@ -27,7 +27,7 @@ class Sieve {
 
 	public int[] getPrimes() {
 		if (primes == null) {
-			primes = new int[(maxNum / (int)Math.log(maxNum)) * 2];
+			primes = new int[(maxNum / ((int)Math.log(maxNum) - 1)) + 1];
 
 			int i = 0;
 			primes[i++] = 2;