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MathNet 2015-part-04 — 191 problems (EN–VI) Question 37

Math Olympiad Vault · MathNet 2015-part-04 — 191 problems (EN–VI)

Question 37

Determine all positive integers $n$ for which there exist positive integers $a_{1}, a_{2}, \ldots, a_{n}$ with
$$
a_{1}+2 a_{2}+3 a_{3}+\ldots+n a_{n}=6 n
$$
and
$$
\frac{1}{a_{1}}+\frac{2}{a_{2}}+\frac{3}{a_{3}}+\ldots+\frac{n}{a_{n}}=2+\frac{1}{n}.
$$