H6_Loops_T6_SumXN

using System;
using System.Numerics;


class SumXn
{
    static void Main()
    {
        Console.WriteLine("Please enter integer x:");
        int x = int.Parse(Console.ReadLine());
        Console.WriteLine("Please enter positive integer n:");
        int n = int.Parse(Console.ReadLine());

        decimal productNFactorial = 1m;

        decimal xPowerN = 1m;

        decimal sumxN = 1m;
        if (n >= 0) // factorial could be calculated from positive integer only. 0!=1
        {
            for (int i = 1; i <= n; i++)
            {
                for (int j = 1; j <= i; j++)
                {
                    productNFactorial = (productNFactorial * j);
                }

                xPowerN = xPowerN * x;
                sumxN = sumxN + (productNFactorial / xPowerN);
                productNFactorial = 1m;
            }


            Console.WriteLine("The result is: {0}", sumxN);
        }
        else
        {
            Console.WriteLine("Invalid input!");
        }
    }
}