Common Sequences
Source: Malaysian SST 2024 P2
September 5, 2024
number theoryDigits
Problem Statement
A finite sequence of decimal digits from is said to be common if for each sufficiently large positive integer , there exists a positive integer such that the expansion of in base ends with this sequence of digits.For example, is common because for any large , the expansion of in base is , whereas is not common because for any squarefree , the expansion of in any base cannot end with .Determine all common sequences.Proposed by Wong Jer Ren