输入一个整数n，计算n个的偶数之和

输入一个整数n，计算n个的偶数之和（注意：不是输入的这个整数以内例如输入:5 就要算5个偶数 2+4+6+8+10）

import java.util.Scanner;

public class learn {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int max = scanner.nextInt();
        int result = 0;
        for (int i = 0; i < max; i++) {
            result += (i + 1) * 2;
        }
        System.out.println(result);
    }
}

public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        long sum = 0;
        for (int i = 1; i <= n; i++) {
            sum += i * 2;
        }
        System.out.println(sum);
        scanner.close();
    }