Editing Keith number (section)

{{Short description|Type of number introduced by Mike Keith}}
{{about|the mathematics concept|the political concept|Countdown with Keith Olbermann}}
In [[recreational mathematics]], a '''Keith number''' or '''repfigit number''' (short for '''rep'''etitive [[Fibonacci sequence|'''F'''ibonacci-like]] d'''igit''') is a [[natural number]] <math>n</math> in a given [[number base]] <math>b</math> with <math>k</math> digits such that when a sequence is created such that the first <math>k</math> terms are the <math>k</math> digits of <math>n</math> and each subsequent term is the sum of the previous <math>k</math> terms, <math>n</math> is part of the sequence. Keith numbers were introduced by [[Mike Keith (mathematician)|Mike Keith]] in 1987.<ref>{{cite journal | author-link = Mike Keith (mathematician) | first = Mike | last = Keith | title = Repfigit Numbers | journal = [[Journal of Recreational Mathematics]] | volume = 19 |issue = 2 | year = 1987 |pages = 41–42}}</ref>
They are computationally very challenging to find, with only about 125 known.