# Definition:Palindromic Number

## Definition

A palindromic number (base $b$) is a number which is a palindrome when expressed in number base $b$.

That is, it reads the same reversed as it does forwards.

When the base is not specified, it is commonplace to understand it as being $10$.

### Sequence

The sequence of palindromic integers in base 10 begins:

$0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 121, 131, \ldots$

## Also see

• Results about palindromic numbers can be found here.

## Linguistic Note

The word palindrome derives from the Ancient Greek παλίνδρομος ‎(palíndromos), meaning running back again.

This is formed from πάλιν ‎(pálin), meaning back, again, and back again, and δρόμος ‎(drómos), meaning running, race, and racecourse.