Huh, do you mean "how can they crop up in maths"? Obviously it's easy to "find" any palindromic number- they will correspond to some number x where you stick x next to its reversed self or where you sit x next to its reversed self without the first digit.
I've seen the process for finding a palindromic number which is the reversal/add way. For example, 186 + 681 = 867+768= 1635. + 5361 = 6996 So 186 gets palindromic at 6996 after 3 steps.
However, a few numbers such at 196 even after 2 million steps has still not become palindromic. Is there any alternative ways of finding palindromic numbers by usuing a different process instead of the reversal/add?