Project Euler - Problem 6

euler.java

package euler;

public class Square {
	
	public static void main(String[] args) {
		System.out.println(sum2(100) - sum(100));
	}
	
	public static int sum(int n) {
		return n*(n+1)*(2*n+1)/6;
	}
	public static int sum2(int n) {
		return n*n*(n+1)*(n+1)/4;
	}
}