题解 | #牛牛学数列4#

public class Main{
    public static void main(String[]args){
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int sum=0;
        for(int i = 1;i<=a;i++){
                sum = sum + i*(i+1)/2;
            
            
        }
        System.out.printf("%d\n",sum);
        
    }//main
}//Main
//