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MathNet 2007-part-03 — 185 problems (EN–VI) Question 24

Math Olympiad Vault · MathNet 2007-part-03 — 185 problems (EN–VI)

Question 24

Let $a_{1}, a_{2}, \ldots, a_{2007}$ be a sequence that contains each of the numbers $1,2, \ldots, 2007$ exactly once. The following operation is now performed repeatedly: if the first term of the sequence equals $n$, the order of the first $n$ terms is reversed. Show that after finitely many such operations the sequence begins with the number $1$.