Around a circle, there are natural numbers. Between every two adjacent numbers, their least common multiple is written. Can these least common multiples form consecutive numbers (arranged in some order)?
(S. Berlov)
Around a circle, there are natural numbers. Between every two adjacent numbers, their least common multiple is written. Can these least common multiples form consecutive numbers (arranged in some order)?
(S. Berlov)
Answer: No.
Solution. Let . Denote the original numbers (in order of traversal) as ; we will assume that . Let . Suppose that the numbers are consecutive natural numbers.
Consider the highest power of two that divides at least one of the numbers . Note that none of the numbers is divisible by . Let, for definiteness, ; then and . Thus, and for some odd and . Without loss of generality, we can assume that . Then, since form consecutive numbers, among them there must be the number (since ). But this number is divisible by (since is even), which is impossible. Contradiction.
Comment. Only the answer - 0 points.
Proved that among the original numbers there are two numbers divisible by (the number is defined in the solution) - 2 points.