Some prime numbers can be expressed as a sum of other consecutives prime numbers

 Some prime numbers can be expressed as a sum of other consecutives prime numbers

for example,

5=2+3,

17=2+3+5+7

41=2+3+5+7+11+13

You task is to find out how many prime numbers which satisfy the property are present in

the range 3 to N subject to a constraint that summation should always start with number 2.

Write a code to find out the number of prime numbers that satisfy the above mentioned

property in a given range


I/P:

13


O/P:

2

5

17

41


SOLUTION:

package Numbers;
import java.util.*;
public class primewithinrange {

    public static boolean isPrime(int n) {
        int count = 0;
        for(int i = 2 ; i <= n ; i++) {
            if(n % i == 0) {
                count++;
            }
        }
        if(count >= 2) {
            return false;
        }
        return true;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        ArrayList<Integer> al = new ArrayList<>();
        for(int i = 2 ; i <= n ; i++) {
            if(isPrime(i)) {
                al.add(i);
            }
        }
        int sum = 0;
        for(int i = 0 ; i <al.size() ; i++) {
            sum = sum + al.get(i);
            if(isPrime(sum)) {
                System.out.println(sum);
            }

        }
    }

    
}

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