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Questions tagged [stirling-numbers]

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7 votes
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Is there any literature on $\sum_{i=1}^{k} \left[ {k \atop i} \right] \zeta(i+1) $?

As per these questions, I'm trying to evaluate $$\sum_{n=2}^{\infty} \big{(} \zeta(n)^{2}-1 \big{)} = 1+ \sum_{m=2}^{\infty} \frac{H_{-\frac{1}{m}}}{m}. $$ Here, $H_{x}$ is a generalized Harmonic ...
Max Lonysa Muller's user avatar
5 votes
0 answers
775 views

A conjecture about the degrees of special polynomials

Define the congruence "modulo m" on exponential Taylor series as $$ \sum_{n=0}^\infty \frac{a_n}{n!}x^n \equiv \sum_{n=0}^\infty \frac{b_n}{n!} x^n \mod m \iff \forall n: \frac{a_n-b_n}{m}\in \mathbb{...
Danil Krotkov's user avatar
4 votes
0 answers
312 views

Positivity of a finite sum involving Stirling numbers of the first kind

Past days I've been trying to prove that certain polynomials have positive coefficients. After a lot of thinking, I came up with a formula for each coefficient individually, and they are not that ugly....
Luis Ferroni's user avatar
  • 1,889
4 votes
0 answers
158 views

Multiple integral evaluation involving Stirling numbers and Riemann zeta function

Hello Mathoverflow community, how are you doing? I just wanted to know if anything is known about the following integral: $$K_n(m) = \overbrace{\int_0^1 \dots \int_0^1}^{n-\mathrm{times}} \left(-\...
Brian's user avatar
  • 1,549
4 votes
0 answers
578 views

A combinatorial bound involving Stirling numbers of the second type

My previous question was solved in a very elegant way, hopefully this (seemingly more complicated) case is also easy for experts. I need the inequality $\Big(\prod^r_{i=1}p_i\Big)\sum^n_{j=0}(-1)^j\...
Dmitry Kerner's user avatar
3 votes
0 answers
89 views

Recursion for reversed rows of the A373183 using unsigned Stirling numbers of the first kind

Let $\left[{n \atop k}\right]$ be unsigned Stirling numbers of the first kind. Here $$ \left[{n \atop k}\right] = (n-1)\left[{n-1 \atop k}\right] + \left[{n-1 \atop k-1}\right], \\ \left[{n \atop 0}\...
Notamathematician's user avatar
3 votes
0 answers
190 views

Stirling number, Delannoy number, and binomial coefficients in a sum

I want to compute/prove that the following sum is positive: $$ \sum_{i = 0}^n \left[\frac{D(n - i, i)}{d} \sum_{j = m}^d s(d, j) \binom{j}{m} (d - i)^{j - m}\right] > 0 $$ where $s(d, j)$ is the ...
Zhi Wang's user avatar
3 votes
0 answers
170 views

Stirling number bounds and polynomials and the Lambert $W$ function

Let $s(n,k)$ be the (signed) Stirling numbers of the first kind. The polynomials $$L_n(x)=\sum_{j=1}^ns(n,n+1-j)\dfrac{x^j}{j!}$$ enter in the asymptotic expansion of the Lambert $W$ function, see for ...
Henri Cohen's user avatar
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2 votes
0 answers
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Generalized identity with Stirling numbers of the second kind and falling factorials

It is known that Striling numbers of the second kind satisfy the relation $$ \sum\limits_{k=0}^{n}{n \brace k}(x)_k = x^n. $$ where $(x)_n$ is the falling factorials such that $$ (x)_n = x(x-1)(x-2)\...
Notamathematician's user avatar
2 votes
0 answers
125 views

Inequality for 2-associated Stirling numbers of the second kind

Let $S_2(n,k)$ denote the 2-associated Stirling number of the second kind for $n$ objects and $k$ blocks, with $n$ being at least two. That is, we partition $n$ labeled objects into $k$ unlabeled ...
Janos Englander's user avatar
1 vote
0 answers
34 views

Closed form for $a(2^m(2k+1))$

Let $a(n)$ be A329369 (i.e., number of permutations of $\{1,2,\dotsc,m\}$ with excedance set constructed by taking $m-i$ ($0 < i < m$) if $b(i-1) = 1$ where $b(k)b(k-1)\cdots b(1)b(0)$ ($0 \...
Notamathematician's user avatar
1 vote
0 answers
86 views

Closed form for the family of polynomials

Let $s(n,k)$ be a (signed) Stirling number of the first kind. Let $R(n,x)$ be the family of polynomials such that $$ R(2n+1,x) = xR(n,x), \\ R(2n,x) = x(R(n,x+1) - R(n, x)), \\ R(0, x) = x $$ Let $\...
Notamathematician's user avatar
1 vote
0 answers
59 views

Simple recursion for the A329369 using Stirling numbers of both kinds

Let $s(n,k)$ be a (signed) Stirling number of the first kind. Let $n \brace k$ be a Stirling number of the second kind. Let $a(n)$ be A329369 (i.e, number of permutations of ${1,2,...,m}$ with ...
Notamathematician's user avatar
1 vote
0 answers
63 views

On the equation involving Stirling numbers of the second kind ${n\brace a}{m\brace b}={k\brace c}$, and its solutions satisfying certain requirements

In this post we denote the Stirling numbers of the second kind as ${r\brace s}$ and we consider the proposal to ask if the equation of the title has infinitely many solutions $${n\brace a}{m\brace b}={...
user142929's user avatar