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MathNet 2020 — Math Olympiad Vault — Part 03 Question 36

Math Olympiad Vault · MathNet 2020 — Math Olympiad Vault — Part 03

Question 36

A sequence of positive integers $a_{1}, a_{2}, a_{3}, \ldots$ satisfies

$$
a_{n+1}=n\left\lfloor\frac{a_{n}}{n}\right\rfloor+1
$$

for all positive integers $n$. If $a_{30}=30$, how many possible values can $a_{1}$ take? (For a real number $x$, $\lfloor x\rfloor$ denotes the largest integer that is not greater than $x$.)