public void TestFor3Digits()
        {
            var result = Prob4.LargestPalindromeProduct(3);

            TestUtils.WriteOut($"Largest palindrome product with 2 3-digit factors is {result}.");
            //906609
            Assert.IsTrue(result == 906609);
        }
        public void PalindromeGenerator()
        {
            int    n    = 1000;
            var    pals = Prob4.PalindromesAtOrBelow(1000).ToArray();
            string s    = $"Palindromes <= {n} are {String.Join(",", pals)}";

            TestUtils.WriteOut(s);

            Assert.IsTrue(pals.Length > 0);
        }
        public void TestFor2Digits()
        {
            var result = Prob4.LargestPalindromeProduct(2);

            Assert.IsTrue(result == 9009);
        }