Series Question

Java program for: 
(1+2)+(1+2+3)+(1+2+3+4)………………….for n terms

int x = 0, sum = 0;

for(int i = 1; i <= n; i++)

{

  for(int j = 1; j <= (i+1); j++)

  {

    x = x + j;

  }

sum = sum + x;

}

System.out.println("Result = "+sum);