Java获取以3位等差的前n项的和

代码如下：

import java.util.ArrayList;

public class GetNumSum {
    public static void main(String[] args) {
        int[] ints = {18, 1, 2, 90, 3};
        sortArr(ints);
        for (int i = 0; i < ints.length; i++) {
            System.out.println(ints[i]);
        }
    }

    
    public static int getNumSum(int srcNum){
        if (srcNum<1 || srcNum>1000){
            System.out.println("输入数据非法！");
            return 0;
        }

        ArrayList integerList = new ArrayList<>();
        int begNum=2;
        for (int i = 0; i < srcNum; i++) {
            integerList.add(begNum);
            begNum+=3;
        }

        System.out.println(integerList);

        int sum=0;
        for (Integer integer : integerList) {
            sum+=integer;
        }

        return sum;
    }

`提示：等差数列求和示例，入参为传递一个项数n，出参为数列和。