A palindromic string:

Check the palindromic property with its list of characters:

A palindromic integer:

This is not palindromic:

Search for palindromic primes:

These are English palindromic words:

These are palindromic decimal integers:

These lists remain invariant under reversal:

To find palindromic sentences, remove whitespace and punctuation characters:

Tetradic numbers remain invariant when flipped back to front and up-down. Hence they only contain digits 0, 1, 8. These are all tetradic numbers with up to five digits:

Some of them are primes:

It is conjectured that this algorithm eventually produces a palindromic number for every decimal input:

There are numbers for which it is not known whether the algorithm succeeds, the smallest being 196:

Find the palindromic Roman numerals up to 1000:

Find the longest palindromic word in French:

The empty list is considered a palindrome:

The null string is considered a palindrome:

One-digit decimal numbers are considered palindromes:

By default, a string is considered palindromic if its list of characters is palindromic:

The first nine coefficients of this series expansion are special palindromic numbers:

Those coefficients can also be generated as squares of repunits 1, 11, 111, etc.: