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# Repdigit

A -repdigit is a number composed of repetition of a single digit (in a given base, generally taken as base 10 unless otherwise specified). For example, the beast number 666 is a (base-10) repdigit. The following table gives the first few repdigits in bases to 10.

 OEIS -repdigits 2 A000225 1, 3, 7, 15, 31, 63, 127, ... 3 A048328 1, 2, 4, 8, 13, 26, 40, 80, 121, ... 4 A048329 1, 2, 3, 5, 10, 15, 21, 42, 63, 85, 170, ... 5 A048330 1, 2, 3, 4, 6, 12, 18, 24, 31, 62, 93, 124, 156, ... 6 A048331 1, 2, 3, 4, 5, 7, 14, 21, 28, 35, 43, 86, 129, 172, ... 7 A048332 1, 2, 3, 4, 5, 6, 8, 16, 24, 32, 40, 48, 57, 114, 171, ... 8 A048333 1, 2, 3, 4, 5, 6, 7, 9, 18, 27, 36, 45, 54, 63, 73, 146, ... 9 A048334 1, 2, 3, 4, 5, 6, 7, 8, 10, 20, 30, 40, 50, 60, 70, 80, 91, 182, ... 10 A010785 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, ...

If the digits of a repdigit are all 1s, it is known as a repunit.

Beast Number, Keith Number, Repunit

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## References

Sloane, N. J. A. Sequences A000225, A010785, A048328, A048329, A048330, A048331, A048332, A048333, and A048334 in "The On-Line Encyclopedia of Integer Sequences."

Repdigit

## Cite this as:

Weisstein, Eric W. "Repdigit." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Repdigit.html