Java Program to print the sum of square series 1^2 +2^2 + ….. +n^2

Java program to print sum of the series 1^2 +2^2 +3^2 +4^2 + ….. +n^2 :

In this tutorial, we will learn how to calculate the sum of the series 1^2 +2^2 +3^2 +4^2 + ….. +n^2 ( where n can be any number ) and print out the series with the sum as well.

Solution :

The sum of the mentioned series is actually much easier than you think. It is (n * (n + 1) * (2 * n + 1 )) / 6 . So, to get the sum we have to calculate the value of this and that’s it. In the program below , I have added one extra function ‘printSeries(int n, int total)’ to visually show the full series and sum of the series as a output. Let’s take a look into the example program and some sample outputs :

Java Example Program :

import java.util.Scanner;

public class Main {

    /**
     * Utility functions
     */
    static void println(String string) {
        System.out.println(string);
    }

    static void print(String string) {
        System.out.print(string);
    }

    /**
     * Print the series
     * @param n : value of n
     * @param total : sum of the series
     */
    static void printSeries(int n, int total) {
        int i = 1;
        for (i = 1; i < n; i++) {
            print(i + "^2 +");
        }
        print(i + "^2 = " + total);
    }


    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        //get value of n from user
        println("Enter value of 'n' : ");
        int n = scanner.nextInt();

        //calculate the sum of the series
        int sum = (n * (n + 1) * (2 * n + 1 )) / 6;

        //print the series
        printSeries(n,sum);

    }
}

Sample Outputs :

Enter value of 'n' : 
8
1^2 +2^2 +3^2 +4^2 +5^2 +6^2 +7^2 +8^2 = 204

Enter value of 'n' : 
7
1^2 +2^2 +3^2 +4^2 +5^2 +6^2 +7^2 = 140

Enter value of 'n' : 
6
1^2 +2^2 +3^2 +4^2 +5^2 +6^2 = 91

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