Patterns /Encodings

Binary Palindromes

Written in base two, these numbers read the same forwards and backwards. 9 is 1001, and 585 is 1001001001.

Matches in range
1,998
Share of all numbers
1 in 501
Out of
1,000,001

Because a binary number always starts with a 1, a binary palindrome must also end with one — so every binary palindrome is odd. That single observation removes half the range immediately.

Base-two symmetry is invisible in decimal, which makes this one of the few traits nobody can spot by eye. It is scored in the representation group precisely because it is a property of notation rather than of the number itself.

A number that is palindromic in both base ten and base two, like 585, is a genuine rarity — and one of the more satisfying results the calculator can return.

Highest-scoring examples

The best-scoring numbers of four digits or more that carry this pattern. Shorter numbers are excluded here because their length alone dominates any score ranking.

Smallest examples

The first numbers in the range that match this pattern.

Related encodings patterns