The sum $\displaystyle\sum\limits_{n=2}^{\infty}\frac{1}{n\ln(n)}$ does not converge.
But the sum $\displaystyle\sum\limits_{n=1}^{\infty}\frac{1}{P_n\ln(P_n)}$ where $P_n$ denotes the $n$th prime number appears to be.
Is that correct, and if so, how can we calculate the value of convergence?
Is it possible that this sum converges to the golden ratio ($\dfrac{1+\sqrt{5}}{2}$)?
Answer
With $P_n \approx n \ln(n)$, we should have $$\sum_{N}^\infty \dfrac{1}{P_n \ln(P_n)} \approx \int_N^\infty \dfrac{dx}{x \ln(x)^2} = \dfrac{1}{\ln N}$$
If the sum for $n$ up to $\pi(19999999) = 1270607$ is $1.57713$, we'd expect
the remainder to be about $.071$, which would push the total to about $1.648$, too high for $\phi$.
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