1 2 4 7规律加到50

import java.util.*;
public class Bubble
{    
    public static void main(String[] args){
    int sum=0;
    int j=1;
     for (int i=0;i<=49 ;i++ )
        {  j=j+i;
       sum=j+sum;
    
     }
 System.out.println(sum);



    }
}