How to print a list with the result of all numbers in a sequence summed with itself? (sequence)

Question

I have this sequence of numbers: 1,2,3. (Can be from 1 to infinity.)

I want to add every number in the sequence to it all, example:

The sequence has 3 numbers.

You have to add in this way:

(1)  
1+1=2  
1+2=3  
1+3=4  

(2)  
2+1=3  
2+2=4  
2+3=5 

(3)  
3+1=4  
3+2=5  
3+3=6 

The program shall print the list with the results of each sequence number separately:

1=(2,3,4)
2=(3,4,5)
3=(4,5,6)

Answer 1

I believe this example does what you need. The class receives the list of elements in the constructor. The sum method iterates twice in a nested form by the list and prints the result.

import java.util.ArrayList;
import java.util.List;

public class SomaLista {

    private List<Integer> lista = null;

    public SomaLista(List<Integer> lista) {
        this.lista = lista;
    }

    public void soma() {
        for (Integer externo : lista) {
            System.out.print(externo + "=");
            List<String> resultado = new ArrayList<String>();
            for (Integer interno : lista) {
                resultado.add(String.valueOf(interno + externo));
            }
            System.out.println("("+String.join(",", resultado)+")");
        }
    }

    public static void main(String args[]) {
        List<Integer> lista = new ArrayList<Integer>();

      for (int i=1; i<=1000000; i++){
  lista.add(i);
        }
        SomaLista sl = new SomaLista(lista);
        sl.soma();
    }

}