144

Part of 1971 All Soviet Union Mathematical Olympiad

Problems(1)

ASU 144 All Soviet Union MO 1971 digits 1 and 2 in decimal such 2^n divides

Source:

Prove that for every natural

n

there exists a number, containing only digits "

1

2

" in its decimal notation, that is divisible by

2^n

n

-th power of two ).

number theorypower of 2Digits