Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
In my opinion, MathOverflow should not be only interested in reference-requests or graduate-level questions. There are some very talented mathematicians (including some Fields Medalists) here. Novel challenging problems (different from well-known open problems) should be allowed.
@user21820 I don't think it is easy to pose a nice and novel conjecture. Your "conjecture" that each $n>5$ with $n\equiv 5\pmod6$ is the sum of a prime and a positive square is not new. Hardy and Littlewood had a conjecture on $p+x^2$.
