Integer Pattern Finder

Reports which of six digit patterns (palindrome, ascending run, descending run, repeated digit, all even digits, all odd digits) each integer's absolute-value digit string matches, listing zero, one, or several matches per line. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-27

Overview

Introduction

Numbers sometimes have neat structural properties in their digits — reading the same backward, climbing steadily upward, or using only even digits — that are easy to overlook when scanning a long list by eye.

This tool checks every integer in a list against six common digit patterns and reports exactly which ones match.

What Is Integer Pattern Finder?

A batch digit-pattern detector: for every integer in the input, it checks the digit string of its absolute value against six named patterns and lists every match.

Patterns are independent of each other, so a single number can match anywhere from zero to all six at once.

How Integer Pattern Finder Works

Each line is parsed as an integer, blank lines are skipped, and invalid lines are rejected before pattern-checking runs.

For each value, the absolute value's digit string is tested against each pattern in turn: reversal equality for palindrome, strict digit-by-digit comparisons for the two run patterns, uniform digit equality for repeated digit, and a parity check across every digit for all-even/all-odd.

Every matching pattern's name is collected and joined with commas after the original value; if nothing matched, the line simply reports "none".

When To Use Integer Pattern Finder

Use it to scan a large batch of numbers for palindromes, monotonic digit runs, or repeated-digit values without checking each one by hand.

It's useful for generating or filtering interesting numbers for puzzles, number-theory explorations, or teaching digit properties.

Often used alongside Integer Decomposer and Integer Digit Shifter.

Features

Advantages

  • Checks all six patterns in a single pass, so you don't need to run separate tools for palindromes versus runs versus parity.
  • Reports every matching pattern per number rather than stopping at the first match, giving a complete picture.

Limitations

  • Patterns are evaluated on the absolute value's digits only; the sign itself is never considered part of any pattern.
  • The six patterns are fixed; this tool can't be extended with a custom, user-defined pattern in the current version.

Examples

A number matching several patterns

Input

1221
307

Output

1221: palindrome
307: none

1221 reads the same forward and backward, so it matches "palindrome" (its digits 1,2,2,1 aren't strictly increasing or decreasing so no run pattern applies, and they're mixed parity so no even/odd pattern applies either); 307 matches none of the six patterns.

A repeated, all-even palindrome

Input

2222

Output

2222: palindrome, repeated digit, all even digits

2222 reads the same backward, every digit is identical, and every digit is even, so it matches three patterns at once.

Best Practices & Notes

Best Practices

  • Remember that run patterns require strict inequality between consecutive digits; a number like 122 (with a repeated digit in the middle) won't match "ascending run".
  • Use Integer Filter first to narrow down a huge list before running the pattern check, if you only care about a subset (e.g. only positive values).

Developer Notes

Each pattern is implemented as an independent boolean check over the digit character array (reversal comparison for palindrome, `Array.every` with an index-aware strict comparison for the two run patterns, and simple `every` checks for repeated-digit and parity), so adding or removing a pattern in the future only touches one self-contained check.

Integer Pattern Finder Use Cases

  • Scanning a batch of numeric IDs or codes for accidental palindromes or repeated-digit values
  • Exploring number-theory curiosities like ascending/descending digit runs across a range of numbers
  • Teaching digit-level pattern recognition and string comparison logic

Common Mistakes

  • Expecting a number with equal, non-strictly-increasing digits (like 122) to match "ascending run" — the run patterns require strictly increasing or strictly decreasing digits, not just non-decreasing.
  • Forgetting that the sign is ignored for pattern matching, so -1221 matches "palindrome" exactly like 1221 does.

Tips

  • Try a run of consecutive integers (like 120-130) through this tool to quickly see how ascending/descending runs and palindromes are distributed nearby.
  • Combine with Integer Decomposer if you want to see the full place-value breakdown of a number alongside its detected patterns.

References

Frequently Asked Questions