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Old 2020-05-18, 12:58   #11
Dr Sardonicus
 
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Feb 2017
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Quote:
Originally Posted by R.D. Silverman View Post
Quote:
Originally Posted by JeppeSN View Post
Yes, I wonder if there is any explanation why the four of them are prime squares. Apparently not. I did check that 2^74207283 - 7 is not a square, ha ha.

Edit: It has been proved that 2^{p+2} - 7 is never going to be square again.

/JeppeSN
Do people not understand the difference between math and numerology?
According to the references in the link, the Diophantine equation

2n - 7 = x2

is called Ramanujan's square equation. He posed the question of whether it has any solutions for n > 15 in 1913.

So I guess you're asking, did he understand the difference between math and numerology?
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