Problem Statement
With a given number n, write a program to find the difference between sum of the squares of and square of sum first n natural numbers.
Example
n = 3 Squares of first three numbers = 3x3 + 2x2 + 1x1 = 9 + 4 + 1 = 14 Squares of sum of first three numbers = (3 + 2 + 1)x(3 + 2 + 1) = 6x6 = 36 Difference = 36 - 14 = 22
Example
Following is the program in Java to find the required difference.
public class JavaTester { public static int difference(int n){ //sum of squares of n natural numbers int sumSquareN = (n * (n + 1) * (2 * n + 1)) / 6; //sum of n natural numbers int sumN = (n * (n + 1)) / 2; //square of sum of n natural numbers int squareSumN = sumN * sumN; //difference return Math.abs(sumSquareN - squareSumN); } public static void main(String args[]){ int n = 3; System.out.println("Number: " + n); System.out.println("Difference: " + difference(n)); } }
Output
Number : 3 Difference: 22