repdigit
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In recreational mathematics, a repdigit or sometimes monodigit is a natural number composed of repeated instances of the same digit in a positional number system (often implicitly decimal). The word is a portmanteau of "repeated" and "digit". Examples are 11, 666, 4444, and 999999. All repdigits are palindromic numbers and are multiples of repunits. Other well-known repdigits include the repunit primes and in particular the Mersenne primes (which are repdigits when represented in binary).
Described at
Schnapszahl
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Encyclopedic overview
8 sectionsContents
- History
- Primes and repunits
- Non-Brazilian composites and repunit powers
- ''k''-Brazilian numbers
- Numerology
- See also
- References
- External links
In recreational mathematics, a repdigit or sometimes monodigit is a natural number composed of repeated instances of the same digit in a positional number system (often implicitly decimal). The word is a portmanteau of "repeated" and "digit". Examples are 11, 666, 4444, and 999999. All repdigits are palindromic numbers and are multiples of repunits. Other well-known repdigits include the repunit primes and in particular the Mersenne primes (which are repdigits when represented in binary).
Any such number can be represented as follows
Excerpted from Wikipedia’s “repdigit” article, available under the CC BY-SA 4.0 licence.