Sum of 1/1! + 1/2! + … + 1/n!

        /// <summary>
        /// O(n) algorithm for calculation Sum of 1/0! + 1/1! + 1/2! + … + 1/n!
        /// </summary>
        /// <param name="n"></param>
        /// <returns></returns>
        private static double SumOfDivFactorial(int n)
        {
            double sum = 1.0d;
            double temp = 1;
            int i = 1;

            while (i < n + 1)
            {

                temp *= i;
                sum += 1.0d / temp;

                i++;
            }

            return sum;
        }