#DidYouKnow: In recreational #Mathematics, a #Repunit is a number like 11, 111, or 1111 that contains only the digit 1 — a more specific type of repdigit. The term stands for repeated unit and was coined in 1966 by Albert H. Beiler in his book Recreations in the Theory of Numbers.

A repunit prime is a repunit that is also a prime number. As of May 2023, the largest known prime number 2^82,589,933 − 1 is a repunit prime.

https://knowledgezone.co.in/kbits/64cf4b1110c4dc6c4fd4b8ed

Mijn kortste stukje ooit voor #NRC. Over het getal 111…111 (op de puntjes staan nog eens 86.447 enen).
#primenumber #uniqueprime #repunit
https://www.nrc.nl/nieuws/2023/06/10/8645386453-a4166620

Odo 11111km: "This was in a little diesel VW Golf we drove at the time. When I looked at that number, I wondered if it were #prime, and further, could such numbers containing only 1’s could ever be prime. [...] This attracted the attention of at least one real mathematician, who introduced the notion of repunits. For example, 1,111,111,111,111,111,111, with 19 digits, is prime; a #repunit prime must have a prime number of digits!"

https://www.tbray.org/ongoing/When/202x/2022/12/04/Long-Links #math #numbers #mathematics