Patterns /Repetition

Numbers With One Repeated Digit

The mildest form of repetition: exactly one digit appears twice, and every other digit is distinct — as in 1231 or 405067.

Matches in range
457,731
Share of all numbers
45.77%
Out of
1,000,001

How long might numbers with one repeated digit take?

1 in 2.2 per roll · 2 rolls on average.

At one daily specimen a day, the mean is about 0 years. A 50% chance takes 2 rolls; 90% takes 4.

7 daily rolls

98.62%

30 daily rolls

100.00%

365 daily rolls

100.00%

100.00% chance of at least one match in 30 independent rolls.

Waiting times are averages, not deadlines. Previous misses do not increase the next roll’s chance. Only Daily Specimens stamp your Atlas.

Find numbers with this pattern →

This is the most common repetition pattern in the range, and the count above makes that plain. A single coincidental match between two digits is close to what random chance predicts, which is why it carries so little information.

Its value in the scoring system is mostly as a floor. A number whose only claim is one repeated pair will not climb far, and seeing that reflected in the score is a useful check that the algorithm is not inflating ordinary numbers.

The birthday problem is the intuition here: once a number has five or six digits drawn from ten values, at least one collision becomes more likely than not.

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 repetition patterns