196-algorithm
The 196-algorithm states that the order of any positive integer of at least two digits can be reversed then added to the original number then that sum reversed and added again repeatedly, finally to form a palindromic number. For example, the reversed order of 38 is 83 so 38 + 83 = 121. The answer is a palindrome. This works for most of these numbers except the numbers 196, 887, 1675, 7436, 13783... (called Lychrel numbers). In 1995 Tim Irvin computed 2,000,000 repetitions of the algorithm on 196 but no palindromes were found.