Repunits and prime numbers
A repunit (“repeated unit”) is a number that only contains the digit 1 in some number base. For example, 31 is a repunit in base 5 and base 2, because 31 is written as 111 (25+5+1) in base 5, and as …
A repunit (“repeated unit”) is a number that only contains the digit 1 in some number base. For example, 31 is a repunit in base 5 and base 2, because 31 is written as 111 (25+5+1) in base 5, and as …