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Pace Nielsen
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Let's use some standard bounds on the $n$th prime, as found in this paper by Pierre Dusart.

We have $$ p_{2n} \leq 2n[\ln(2n)+\ln(\ln(2n))-0.9484] = 2n\left[\ln(n)+\ln\left(\frac{2}{e^{0.9484}}\ln(2n)\right)\right] $$ using an iequalityinequality stated on page 414 of the cited paper, valid for $n\geq 19509$. On the other hand, we have $$2n\ln(p_n)\geq 2n\ln[n(\ln(n)+\ln(\ln(n))-1)]=2n[\ln(n)+\ln(\ln(n\ln(n)/e))] $$ by the main result of that paper, for $n\geq 2$.

Thus, your desired inequality will be true once $n\geq 19509$ and when $$\frac{2}{e^{0.9484}}\ln(2n)<\ln\left(\frac{n\ln(n)}{e}\right). $$ That last inequality becomes true when $n\geq 13$. Then a simple check will show that the inequality you want is valid in the region $52\leq n\leq 19509$.

Let's use some standard bounds on the $n$th prime, as found in this paper by Pierre Dusart.

We have $$ p_{2n} \leq 2n[\ln(2n)+\ln(\ln(2n))-0.9484] = 2n\left[\ln(n)+\ln\left(\frac{2}{e^{0.9484}}\ln(2n)\right)\right] $$ using an iequality stated on page 414 of the cited paper, valid for $n\geq 19509$. On the other hand, we have $$2n\ln(p_n)\geq 2n\ln[n(\ln(n)+\ln(\ln(n))-1)]=2n[\ln(n)+\ln(\ln(n\ln(n)/e))] $$ by the main result of that paper, for $n\geq 2$.

Thus, your desired inequality will be true once $n\geq 19509$ and when $$\frac{2}{e^{0.9484}}\ln(2n)<\ln\left(\frac{n\ln(n)}{e}\right). $$ That last inequality becomes true when $n\geq 13$. Then a simple check will show that the inequality you want is valid in the region $52\leq n\leq 19509$.

Let's use some standard bounds on the $n$th prime, as found in this paper by Pierre Dusart.

We have $$ p_{2n} \leq 2n[\ln(2n)+\ln(\ln(2n))-0.9484] = 2n\left[\ln(n)+\ln\left(\frac{2}{e^{0.9484}}\ln(2n)\right)\right] $$ using an inequality stated on page 414 of the cited paper, valid for $n\geq 19509$. On the other hand, we have $$2n\ln(p_n)\geq 2n\ln[n(\ln(n)+\ln(\ln(n))-1)]=2n[\ln(n)+\ln(\ln(n\ln(n)/e))] $$ by the main result of that paper, for $n\geq 2$.

Thus, your desired inequality will be true once $n\geq 19509$ and when $$\frac{2}{e^{0.9484}}\ln(2n)<\ln\left(\frac{n\ln(n)}{e}\right). $$ That last inequality becomes true when $n\geq 13$. Then a simple check will show that the inequality you want is valid in the region $52\leq n\leq 19509$.

Source Link
Pace Nielsen
  • 18.7k
  • 4
  • 75
  • 137

Let's use some standard bounds on the $n$th prime, as found in this paper by Pierre Dusart.

We have $$ p_{2n} \leq 2n[\ln(2n)+\ln(\ln(2n))-0.9484] = 2n\left[\ln(n)+\ln\left(\frac{2}{e^{0.9484}}\ln(2n)\right)\right] $$ using an iequality stated on page 414 of the cited paper, valid for $n\geq 19509$. On the other hand, we have $$2n\ln(p_n)\geq 2n\ln[n(\ln(n)+\ln(\ln(n))-1)]=2n[\ln(n)+\ln(\ln(n\ln(n)/e))] $$ by the main result of that paper, for $n\geq 2$.

Thus, your desired inequality will be true once $n\geq 19509$ and when $$\frac{2}{e^{0.9484}}\ln(2n)<\ln\left(\frac{n\ln(n)}{e}\right). $$ That last inequality becomes true when $n\geq 13$. Then a simple check will show that the inequality you want is valid in the region $52\leq n\leq 19509$.