The only prime of the form n^2-4 is 5?

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SUMMARY

The only prime number of the form n^2-4 is definitively 5. This conclusion is reached by assuming p is a prime such that p=n^2-4, which can be factored into (n+2)(n-2). Given that n+2 is always greater than 1 for all natural numbers n, the only solution occurs when n-2 equals 1, leading to n=3 and confirming p=5. Thus, the proof is validated by multiple participants in the discussion.

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Homework Statement
Prove the assertion below:
The only prime of the form n^2-4 is 5.
Relevant Equations
None.
Proof: Suppose p is a prime such that p=n^2-4.
Then we have p=n^2-4=(n+2)(n-2).
Note that prime number is a number that has only two factors,
1 and the number itself.
Since n+2>1 for ##\forall n \in \mathbb{N}##,
it follows that n-2=1, and so n=1+2=3.
Thus p=n^2-4=3^2-4
=9-4
=5.
Therefore, the only prime of the form n^2-4 is 5.

Above is my proof for this assertion. Can anyone please verify/review it and see if it's correct?
 
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Same here. Correct.
 
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fresh_42 said:
Same here. Correct.
Thank you!
 

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