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Feb 7, 2021 at 22:13 comment added Stanley Yao Xiao Even in the simplest cases this type of question is almost impossible to answer. For example, suppose we are looking at the equation $x^2 - 2y^2 = \pm 1$. The solutions are generated by $1 + \sqrt{2}$, by looking at the rational/irrational parts of $(1 + \sqrt{2})^n$. The rational parts are given by $\sum_{j=0}^{\lfloor n/2 \rfloor} \binom{n}{2j} 2^j$. Asking whether this is prime infinitely often is already well-beyond what we know how to do: we can't even answer this question for the easier looking sequence $2^k - 1$ (the Mersenne sequence).
Feb 7, 2021 at 21:54 answer added Will Jagy timeline score: 2
Feb 7, 2021 at 21:06 history edited JoshuaZ CC BY-SA 4.0
correct initial equation and add parenthetical note.
Feb 7, 2021 at 21:05 comment added JoshuaZ @WillJagy Ah yes, there should be an $f$ term in the original. Good catch.
Feb 7, 2021 at 20:58 comment added Will Jagy for p,q to be the variables, your general quadratic needs to have a constant term $f$ to accommodate the $ma^2$
S Feb 7, 2021 at 20:20 history suggested gmvh
Added top-level tag
Feb 7, 2021 at 20:11 review Suggested edits
S Feb 7, 2021 at 20:20
Feb 7, 2021 at 20:05 history edited JoshuaZ CC BY-SA 4.0
delete redundant word
Feb 7, 2021 at 18:05 history edited JoshuaZ CC BY-SA 4.0
fix right to left, and expand sum note
Feb 7, 2021 at 18:03 comment added JoshuaZ @dodd Sorry, that should be the left hand side.
S Feb 7, 2021 at 18:03 history suggested markvs CC BY-SA 4.0
Fixed misprint in the title
Feb 7, 2021 at 18:03 comment added markvs "barring the exceptional case where the right-hand side itself factors"? The RHS is $0$.
Feb 7, 2021 at 18:02 review Suggested edits
S Feb 7, 2021 at 18:03
Feb 7, 2021 at 17:41 history asked JoshuaZ CC BY-SA 4.0