9

This number is a composite.

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The smallest composite number n such that both 2n+n and 2n-n are prime. That is, 29+9 = 521 and 29-9 = 503 are prime. [Poo Sung]

Submitted: 2009-06-03 07:02:59;   Last Modified: 2009-06-03 10:56:56.
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