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0 votes
0 answers
34 views

Asymptotic expansions of sums via Cauchy's integral formula and Watson's lemma

I am looking for references that deal with the asymptotic expansions of sums of the form $$s(n)=\sum_{k=0}^n g(n,k)$$ using the (or similar to) following method. We have the generating function $$f(z)=...
bob's user avatar
  • 2,249
12 votes
2 answers
504 views

How to determine the value of $\displaystyle f(x) = \sum_{n=1}^\infty\frac{\sqrt n}{n!}x^n$?

How to determine the value of $\displaystyle f(x) = \sum_{n=1}^\infty\frac{\sqrt n}{n!}x^n$? No context, this is just a curiosity o'mine. Yes, I am aware there is no reason to believe a random power ...
Alma Arjuna's user avatar
  • 3,881
2 votes
0 answers
131 views

Generating function of Clausen functions: $\displaystyle\sum_{n=1}^\infty \text{Cl}_{2n}(x)\frac{t^{2n}}{(2n)!}$

Context I was trying to solve a series: $$\sum_{k=2}^{\infty}\zeta'(k)x^{k-1}$$ Using the Fourier series \begin{equation} \begin{split} \log\Gamma(x)&=\frac{\ln(2\pi)}{2}+\sum_{k=1}^\infty \frac{\...
Math Attack's user avatar
1 vote
0 answers
72 views

Evaluate $\sum\limits_{n=0}^\infty\operatorname W(e^{e^{an}})x^n$ with Lambert W function

$\def\W{\operatorname W} \def\Li{\operatorname{Li}} $ Interested by $\sum_\limits{n=1}^\infty\frac{\W(n^2)}{n^2}$, here is an example where Lagrange reversion applies to a Lambert W sum: $$\W(x)=\ln(...
Тyma Gaidash's user avatar
3 votes
1 answer
502 views

Generating function of the polylogarithm.

Let $\operatorname{Li}_s(z)$ denote the polylogarithm function $$\operatorname{Li}_s(z) = \sum_{k=1}^\infty \frac{z^k}{k^s}.$$ Does there exists a closed form or a known function which generates the ...
Dr Potato's user avatar
  • 812
9 votes
5 answers
2k views

A group of important generating functions involving harmonic number.

How to prove the following identities: $$\small{\sum_{n=1}^\infty\frac{H_{n}}{n^2}x^{n}=\operatorname{Li}_3(x)-\operatorname{Li}_3(1-x)+\ln(1-x)\operatorname{Li}_2(1-x)+\frac12\ln x\ln^2(1-x)+\zeta(3)...
Ali Shadhar's user avatar
  • 25.8k