FirstFactorial.cs

        public static int FirstFactorial(int num)
        {
            int[] memory = new int[num+1];
            
           for(int i = 0; i < num+1; i ++)
            { 
                    memory[i] = i;             
            }

            num = 1;
            for(int x=0; x < memory.Length; x ++ )
            {
                if(x>0)
                num = num * memory[x];
            }


            return num;

        }

8 returns = 40320