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MathNet 2009-part-02 — 175 problems (EN–VI) Question 34

Math Olympiad Vault · MathNet 2009-part-02 — 175 problems (EN–VI)

Question 34

A positive integer $N$ is called balanced, if $N=1$ or if $N$ can be written as a product of an even number of not necessarily distinct primes. Given positive integers $a$ and $b$, consider the polynomial $P$ defined by $P(x)=(x+a)(x+b)$.

a. Prove that there exist distinct positive integers $a$ and $b$ such that all the numbers $P(1), P(2), \ldots, P(50)$ are balanced.

b. Prove that if $P(n)$ is balanced for all positive integers $n$, then $a=b$.