题解 | #牛牛学数列4#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int sum = 0;
        for (int i = 1; i <= n; i++) {
            int count = 0;
            for (int j = 1; j <= i; j++ ) {
                count += j;
            }
            sum += count;
        }
        System.out.println(sum);
    }
}