MathDB
b-ary Fibonacci Numbers

Source: 2018 RMM Shortlist N2

February 21, 2019
number theoryFibonacci

Problem Statement

Prove that for each positive integer kk there exists a number base bb along with kk triples of Fibonacci numbers (Fu,Fv,Fw)(F_u,F_v,F_w) such that when they are written in base bb, their concatenation is also a Fibonacci number written in base bb. (Fibonacci numbers are defined by F1=F2=1F_1 = F_2 = 1 and Fn+2=Fn+1+FnF_{n+2} = F_{n+1} + F_n for all positive integers nn.)
Proposed by Serbia