Editing Palindromic number (section)

{{Short description|Number that remains the same when its digits are reversed}}
A '''palindromic number''' (also known as a '''numeral palindrome''' or a '''numeric palindrome''') is a number (such as 16361) that remains the same when its digits are reversed. In other words, it has [[reflectional symmetry]] across a vertical axis. The term ''palindromic'' is derived from [[palindrome]], which refers to a word (such as ''rotor'' or ''racecar'') whose spelling is unchanged when its letters are reversed. The first 30 palindromic numbers (in [[decimal]]) are:
:  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, ... {{OEIS|id=A002113}}.

Palindromic numbers receive most attention in the realm of [[recreational mathematics]]. A typical problem asks for numbers that possess a certain property ''and'' are palindromic. For instance:
* The [[palindromic prime]]s are 2, 3, 5, 7, 11, 101, 131, 151, ... {{OEIS|id=A002385}}.
* The palindromic [[square number]]s are 0, 1, 4, 9, 121, 484, 676, 10201, 12321, ... {{OEIS|id=A002779}}.

In any [[radix|base]] there are [[Infinite set|infinitely many]] palindromic numbers, since in any base the infinite [[sequence]] of numbers written (in that base) as 101, 1001, 10001, 100001, etc. consists solely of palindromic numbers.