3 Divisors Java

PROGRAM TO PRINT NUMBERS WITH EXACTLY THREE DIVISORS

import java.io.*;

import java.util.*;

  

class MAIN

{

    // Generates all primes upto n and prints their squares

    static void numbersWith3Divisors(int n)

    {

        boolean[] prime = new boolean[n+1];

        Arrays.fill(prime, true);

        prime[0] = prime[1] = false;

   

        for (int p=2; p*p<=n; p++)

        {

            // If prime[p] is not changed, then it is a prime

            if (prime[p] == true)

            {

                // Update all multiples of p

                for (int i=p*2; i<=n; i += p)

                    prime[i] = false;

            }

        }

   

        // print squares of primes upto n

        System.out.println("Numbers with 3 divisors : ");

        for (int i=0;  i*i <= n ; i++)

            if (prime[i])

                System.out.print(i*i + " ");

    }

      

    // driver program

    public static void main (String[] args) 

    {

        int n = 96;

        numbersWith3Divisors(n); 

    }

}

OUTPUT

Numbers with 3 divisors :
4 9 25 49 

CREDITS: https://www.geeksforgeeks.org/numbers-exactly-3-divisors/