Determine n

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Katy729
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Joined: Sat May 06, 2017 2:30 am

Determine n

Unread post by Katy729 » Sun May 21, 2017 2:44 am

Determine if there are integers $n$ so that $n^2-4$ has exactly $10$ divisors (positive).

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asif e elahi
Posts: 183
Joined: Mon Aug 05, 2013 12:36 pm
Location: Sylhet,Bangladesh

Re: Determine n

Unread post by asif e elahi » Fri Jun 02, 2017 8:49 am

Sketch:
Suppose $n$ is such an integer. Prove that $n^2-4=pq^4$ for some prime $p,q$. Deduce that $q=2$.......

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