Repdigits Base $b$ as Difference of Two Fibonacci Numbers

Repdigits Base $b$ as Difference of Two Fibonacci Numbers

Year:    2022

Author:    Zafer Şiar, Fatih Erduvan, Refik Keskin

Journal of Mathematical Study, Vol. 55 (2022), Iss. 1 : pp. 84–94

Abstract

In this paper, we find all repdigits expressible as difference of two Fibonacci numbers in base $b$ for $2\leq b\leq10.$ The largest repdigits in base $b$, which can be written as difference of two Fibonacci numbers are \begin{align*}&F_{9}-F_{4}=34-3=31=(11111)_{2},~~~~~~\text{ }F_{14}-F_{7}=377-13=364=(111111)_{3},\\&F_{14}-F_{7}=377-13=364=(222)_{4},~~ \text{ }F_{9}-F_{4}=34-3=31=(111)_{5},\\&F_{11}-F_{4}=89-3=86=(222)_{6},~~~~~~~~\text{ }F_{13}-F_{5}=233-5=228=(444)_{7},\\&F_{10}-F_{2}=55-1=54=(66)_{8},~~~~~~~~~~\text{ }F_{14}-F_{7}=377-13=364=(444)_{9},\end{align*} and $$F_{15}-F_{10}=610-55=555=(555)_{10}.$$

As a result, it is shown that the largest Fibonacci number which can be written as a sum of a repdigit and a Fibonacci number is $F_{15}=610=555+55=555+F_{10}.$

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Journal Article Details

Publisher Name:    Global Science Press

Language:    English

DOI:    https://doi.org/10.4208/jms.v55n1.22.07

Journal of Mathematical Study, Vol. 55 (2022), Iss. 1 : pp. 84–94

Published online:    2022-01

AMS Subject Headings:   

Copyright:    COPYRIGHT: © Global Science Press

Pages:    11

Keywords:    Fibonacci numbers repdigit Diophantine equations linear forms in logarithms.

Author Details

Zafer Şiar

Fatih Erduvan

Refik Keskin