Loops - Equation S = 1 + 1!/X^N

using System;

class EquationNX
{
    static void Main(string[] args)
    {
        bool successParse;
        decimal enteredN, enteredX;
        enteredX = 1;
        decimal constantX;
        decimal factorielN = 1;
        decimal squareX;


        do
        {
            Console.Write("Enter N: ");
            successParse = decimal.TryParse(Console.ReadLine(), out enteredN);
            if (successParse)
            {
                Console.Write("Enter X: ");
                successParse = decimal.TryParse(Console.ReadLine(), out enteredX);
            }

            else
            {
                Console.WriteLine("Error!");
            }

        } while (!successParse);

        decimal sum = 1 + 1 / enteredX;
        squareX = enteredX;
        for (int i = 2; i <= enteredN; i++)
        {
            factorielN = factorielN *i;
            squareX = squareX * enteredX;

            sum = sum + (factorielN/squareX);
            Console.WriteLine("factorielN/squareX: {0}", factorielN / squareX);
            Console.WriteLine("Sum: {0}", sum);
        }

        Console.WriteLine("The answer is: {0}",sum);
    }

}