using System;

public class Program

{

        public static void Main(string[] args)

        {   

            //Change the array values to the desired inputs

            int [] nValues = {0,2,5,10,20};

            foreach(int nValue in nValues)

            {

                Console.WriteLine("When n = {0}, the sum of '0 to n' is {1}", nValue, calculateSum(nValue));

            }             

        }

        public static int calculateSum(int n)

        {

            int totalSum = n;

            for (int i = 1; i<n; i++)

            totalSum += i;

            return (totalSum);

        }

​

}