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2 votes
2 answers
222 views
+100

$\operatorname{Li}_{2} \left(\frac{1}{e^{\pi}} \right)$ as a limit of a sum

Working on the same lines as This/This and This I got the following expression for the Dilogarithm $\operatorname{Li}_{2} \left(\frac{1}{e^{\pi}} \right)$: $$\operatorname{Li}_{2} \left(\frac{1}{e^{\...
Srini's user avatar
  • 814
0 votes
0 answers
88 views

$\operatorname{Li}_{2} \left(\frac12 \right)$ vs $\operatorname{Li}_{2} \left(-\frac12 \right)$ : some long summation expressions

Throughout this post, $\operatorname{Li}_{2}(x)$ refers to Dilogarithm. While playing with some Fourier Transforms, I came up with the following expressions: $$2 \operatorname{Li}_{2}\left(\frac12 \...
Srini's user avatar
  • 814
4 votes
1 answer
224 views

Closed form for $\sum\limits_{M=2}^{\infty}\sum\limits_{n=M}^{\infty} \frac{2^{-M}3^{M-n-1}\pi \csc(n \pi) \Gamma(M)}{(n+1)^2 \Gamma(M-n)\Gamma(n+1)}$

I encountered this expression generated by mathematica as a sub-step in a problem I am solving. $$\sum\limits_{M=2}^{\infty}\sum\limits_{n=M}^{\infty} \frac{2^{-M}3^{M-n-1}\pi \csc(n \pi) \Gamma(M)}{(...
Srini's user avatar
  • 814
3 votes
1 answer
116 views

Is there a closed form solution for the sum $\sum\limits_{M=2}^{\infty} \sum\limits_{n=M}^{\infty} \frac{2^{-M}3^{M-n-1}}{(M-n-1)(n+1)^{2}}$?

While working on another problem, this came up as a sub-step: $$ \sum_{M\ =\ 2}^{\infty}\,\,\,\sum_{n\ =\ M}^{\infty}\ {2^{-M}\ 3^{M - n - 1} \over \left(M - n - 1\right)\left(n + 1\right)^{\,2}} $$ ...
Srini's user avatar
  • 814
2 votes
0 answers
140 views

The ultimate polylogarithm ladder

As you can see, here I performed a derivation of a quite simple formula, not much differing from the standard integral representation of the Polylogarithm. Seeking to make it fancier, I arrived at ...
Artur Wiadrowski's user avatar
1 vote
0 answers
68 views

Polylogarithm further generalized

Here I proposed a generalized formula for the polylogarithm. However, because of a slight mistake towards the end, visible prior to the edit, I was unaware that it yields just a result of an integral ...
Artur Wiadrowski's user avatar
2 votes
1 answer
255 views

Generalized formula for the polylogarithm

Some time ago, I discovered the formula for repeated application of $z\frac{d}{dz}$ here. Recently, I thought about taking the function to which this would be applied to be the integral representation ...
Artur Wiadrowski's user avatar
0 votes
1 answer
98 views

Converting a 2D lattice sum into a sum over 1D lattice sums in a circle

I'm working on a physics problem. I have a lattice sum, which in 1D is a sum over a linear chain. It reads $$ f_k = \sum_{n=1}^\infty \frac{2\cos(kn)}{n^3}. $$ This can be written in terms of ...
Tom's user avatar
  • 510
2 votes
0 answers
75 views

The summation $\sum_{k=1}^{\infty} \frac{\phi^{-2k}}{k^2}=\text{Li}_2(1/\phi^2)=\frac{\pi^2}{15}-\ln^2 \phi$ [duplicate]

In a recent post Computing $\int_0^{1/2}\frac{\sinh^{-1}(u)}{u} \,du=\frac{\pi^2}{20}$, $\zeta(2)=\frac53 \sum_{n=0}^\infty \frac{(-1)^n\binom{2n}{n}}{2^{4n}(2n+1)^2}$ I evaluated the required ...
Z Ahmed's user avatar
  • 43.5k
3 votes
3 answers
392 views

Logarithmic integral $ \int_0^1 \frac{x\ln x\ln(1+x)}{1+x^2}\ \mathrm{d}x $

I found this integral weeks ago. $$ \int_0^1 \dfrac{x\ln(x)\ln(1+x)}{1+x^2}\ \mathrm{d}x $$ I tried to solve this integral using various series representation and ended up with a complicated double ...
Laxmi Narayan Bhandari's user avatar
1 vote
1 answer
59 views

Further Stirling number series resummation

\begin{equation} \sum_{m=1}^\infty\sum_{n=1}^\infty (-1)^{n } \frac{S_m^{(3)}}{m! n}(-1 + u)^{(m + n - 1)} (\frac{x}{-1 + x})^m \end{equation} Note: $S^{(3)}_m$ belongs to the Stirling number of the ...
YU MU's user avatar
  • 99
0 votes
0 answers
59 views

Stirling number series resummation

\begin{equation}\sum_{m=1}^{\infty}\frac{a_1^3 S_m^{(3)} (u-1)^{m-1} \left(\frac{x}{x-1}\right)^m}{m!}\end{equation} Does somebody know the result of this resummation? Note: $S_m^{(3)} $ belongs to ...
YU MU's user avatar
  • 99
0 votes
0 answers
82 views

General expression of a triangle sequence

\begin{gather*} \frac{1}{4} \\ \frac{1}{4} \quad \frac{1}{4} \\ \frac{11}{48} \quad \frac{1}{4} \quad \frac{11}{48} \\ \frac{5}{24} \quad \frac{11}{48} \quad \frac{11}{48} \quad \frac{5}{24} \\ \frac{...
YU MU's user avatar
  • 99
0 votes
1 answer
101 views

What's this partial sum $ \sum_{k=0}^{n-1} \dfrac{\log(k!)}{2^{k+1}}$ equal?

I want to get this partial sum of $$ \sum_{k=0}^{n-1} \dfrac{\log(k!)}{2^{k+1}}$$ which it is convergent and it is closed to one half , I have tried to use polylogarithm function which is defined as :...
zeraoulia rafik's user avatar
32 votes
1 answer
817 views

On the relationship between $\Re\operatorname{Li}_n(1+i)$ and $\operatorname{Li}_n(1/2)$ when $n\ge5$

Motivation $\newcommand{Li}{\operatorname{Li}}$ It is already known that: $$\Re\Li_2(1+i)=\frac{\pi^2}{16}$$ $$\Re\Li_3(1+i)=\frac{\pi^2\ln2}{32}+\frac{35}{64}\zeta(3)$$ And by this question, ...
Kemono Chen's user avatar
  • 8,669

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