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I was playing around with the prime counting function and came across something that seemed correct to me, maybe it's already been proven but I don't know so I decided to ask here.

maybe a stupid question but whatever

Is $$\pi((n+1)^2) < \frac{(n+2)^2}{\ln((n+2)^2)}$$ for $n>0$?

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    $\begingroup$ Is there a reason this question is framed in terms of $n+1$ and not $n$ ($\pi(n^2) < \frac{(n+1)^2}{\ln((n+1)^2)}$)? $\endgroup$ Commented Nov 14, 2023 at 5:21
  • $\begingroup$ You wrote: "I still don't know how to write mathematical expressions". You can check whether the edits make this into the equation you wanted to write. You can find some useful pointers here: How does one type mathematical formulas on this site? $\endgroup$ Commented Nov 14, 2023 at 5:22
  • $\begingroup$ This doesn't follow from fairly strong non-asymptotic bounds on the prims counting function, and I think it fails if $\pi(n^2) > \text{li}(n^2)$, see Skewes's number, so it should fail sometimes for big numbers. It might follow from weaker results on deviations of the prime counting function, I'm not sure $\endgroup$ Commented Nov 14, 2023 at 5:36

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A numerical calculation (in, say, Wolfram Alpha or Mathematica) shows that if $x \geq e$, then $$\frac{(\sqrt{x}+1)^2}{2\log(1+\sqrt{x})}<\frac{x}{\log x}\Big(1+\frac{1}{\log x}+\frac{2}{(\log x)^2}\Big).$$ Moreover, Pierre Dusart proved that if $x\geq 88,879$, then $$ \frac{x}{\log x}\Big(1+\frac{1}{\log x}+\frac{2}{(\log x)^2}\Big)<\pi(x). $$ Therefore, if $x\geq 88,879$, then $$ \frac{(\sqrt{x}+1)^2}{2\log(1+\sqrt{x})}<\pi(x). $$ Under the change of variables $n=\sqrt{x}-1$, we find that if $n\geq 297$, then $$ \frac{(n+2)^2}{\log[(n+2)^2]}<\pi((n+1)^2). $$ ADDED: An additional numerical calculation shows that the only positive integers $n$ such that $$\pi((n+1)^2)<\frac{(n+2)^2}{\log[(n+2)^2]}$$ are $1$, $2$, $3$, $4$, $5$, $6$, $7$, and $9$.

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