Decimal Representation – 2^m Starting with Specific Digits

number theory

Given a finite sequence of decimal digits $a_1,a_2,…,a_n$ prove that there exists a natural number $m$ such that decimal representation of $2^m$ starts with that sequence of digits.

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Best Answer

Hint: $\log 2$ is irrational. What can you say about $ \{ n log 2 \}$, the fractional parts?

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