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Let $r_k(C_{2m+1})$ be the $k$-color Ramsey number of an odd cycle $C_{2m+1}$ of length $2m+1$. It is shown that for each fixed $m\ge2$, \[r_k(C_{2m+1})<c^{k}\sqrt{k!}\] for all sufficiently large $k$, where $c=c(m)>0$ is a constant. This…

Combinatorics · Mathematics 2018-10-25 Qizhong Lin , Weiji Chen

The $3x+1$ Problem asks if whether for every natural number $n$, there exists a finite number of iterations of the piecewise function $$f(2n)=n, \quad f(2n-1)=6n-2, $$ with an iterate equal to the number $1$, or in other words, every…

Number Theory · Mathematics 2015-04-14 Jeffrey R. Goodwin

In this paper, we consider nine OEIS sequences, the analysis of which allows us to find a connection between Motzkin numbers and Fibonacci numbers. In each Motzkin number, we distinguish an even component and an odd component, the…

Combinatorics · Mathematics 2021-08-25 Gennady Eremin

We show that for any positive integer $r$ there exists an integer $k$ and a $k$-colouring of the edges of $K_{2^{k}+1}$ with no monochromatic odd cycle of length less than $r$. This makes progress on a problem of Erd\H{o}s and Graham and…

Combinatorics · Mathematics 2017-01-17 A. Nicholas Day , J. Robert Johnson

The following special case of a conjecture by Loehr and Warrington was proved recently by Ekhad, Vatter, and Zeilberger: There are 10^n zero-sum words of length 5n in the alphabet {+3,-2} such that no zero-sum consecutive subword that…

Combinatorics · Mathematics 2016-09-07 Jonas Sjostrand

Let $\mathbb{F}_{p^m}$ be a finite field of cardinality $p^m$ and $R=\mathbb{F}_{p^m}[u]/\langle u^2\rangle=\mathbb{F}_{p^m}+u\mathbb{F}_{p^m}$ $(u^2=0)$, where $p$ is an odd prime and $m$ is a positive integer. For any $\alpha,\beta\in…

Information Theory · Computer Science 2015-11-11 Yuan Cao , Qingguo Li

In this paper we resolve the arithmetic analogues of standard conjectures for an arithmetic variety, which are proposed by Gillet and Soule, into original standard conjectures and similar conjectures for two cycle class groups. One is the…

alg-geom · Mathematics 2008-02-03 Yuichiro Takeda

We study the problem of finding homomorphisms into odd cycles from planar graphs with high odd-girth. The Jaeger-Zhang conjecture states that every planar graph of odd-girth at least $4k+1$ admits a homomorphism to the odd cycle $C_{2k+1}$.…

Combinatorics · Mathematics 2024-02-06 Daniel W. Cranston , Jiaao Li , Zhouningxin Wang , Chunyan Wei

We prove that for each odd integer $k \geq 7$, every graph on $n$ vertices without odd cycles of length less than $k$ contains at most $(n/k)^k$ cycles of length $k$. This generalizes the previous results on the maximum number of pentagons…

Combinatorics · Mathematics 2021-09-07 Andrzej Grzesik , Bartłomiej Kielak

We prove two positivity conjectures proposed by Guo for alternating sums and factorial ratios built from Gaussian coefficients. The first result proves the positivity of the odd $q$-super Catalan numbers \[…

Combinatorics · Mathematics 2026-05-28 Ji-Cai Liu

In the proof of the irrationality of $\zeta(3)$ and $\zeta(2)$, Ap\'ery defined two integer sequences through $3$-term recurrences, which are known as the famous Ap\'ery numbers. Zagier, Almkvist--Zudilin and Cooper successively introduced…

Number Theory · Mathematics 2024-06-27 Ji-Cai Liu

Except for Koshy who devotes seven pages to applications of Fibonacci Numbers to electric circuits, most books and the Fibonacci Quarterly have been relatively silent on applications of graphs and electric circuits to Fibonacci numbers.…

Combinatorics · Mathematics 2022-07-27 Emily J. Evans , Russell J. Hendel

It is known that the number of permutations in the symmetric group $S_{2n}$ with cycles of odd lengths only is equal to the number of permutations with cycles of even lengths only. We prove a refinement of this equality, involving descent…

Combinatorics · Mathematics 2025-02-07 Ron M. Adin , Pál Hegedűs , Yuval Roichman

The well-known $abc$-conjecture concerns triples $(a,b,c)$ of non-zero integers that are coprime and satisfy ${a+b+c=0}$. The strong $n$-conjecture is a generalisation to $n$ summands where integer solutions of the equation ${a_1 + \ldots +…

Number Theory · Mathematics 2025-07-17 Rupert Hölzl , Sören Kleine , Frank Stephan

We derive a general recurrence relation for squares of Fibonacci-like numbers. Various properties are developed, including double binomial summation identites.

General Mathematics · Mathematics 2019-01-09 Kunle Adegoke , Tokunbo Omiyinka

Let D be the circulant digraph with n vertices and connection set {2,3,c}. (Assume D is loopless and has outdegree 3.) Work of S.C.Locke and D.Witte implies that if n is a multiple of 6, c is either (n/2) + 2 or (n/2) + 3, and c is even,…

Combinatorics · Mathematics 2007-05-23 Dave Witte Morris , Joy Morris , Kerri Webb

The enumeration of Hamiltonian cycles on 2n*2n grids of nodes is a longstanding problem in combinatorics. Previous work has concentrated on counting all cycles. The current work enumerates nonisomorphic cycles -- that is, the number of…

Combinatorics · Mathematics 2014-02-05 Ed Wynn

Let $c\phi_{k}(n)$ be the $k$-colored generalized Frobenius partition function. By employing the generating function of $c\phi_{6}(3n+1)$ found by Hirschhorn, we prove that $c\phi_{6}(27n+16)\equiv 0$ (mod 243). This confirms a conjecture…

Number Theory · Mathematics 2015-07-14 Liuquan Wang

Polignac [1] conjectured that for every even natural number $2k (k\geq1)$, there exist infinitely many consecutive primes $p_n$ and $p_{n+1}$ such that $p_{n+1}-p_n=2k$. A weakened form of this conjecture states that for every $k\geq1$,…

General Mathematics · Mathematics 2009-09-14 Shaohua Zhang

We give a quintet of proofs resulting from questions posed by Erd\H{o}s. These questions concern ordinary lines in planar point sets, sequences with uniformly small exponential sums, $K_4$-free $4$-critical graphs with few chords in any…

Combinatorics · Mathematics 2026-04-09 Boris Alexeev , Moe Putterman , Mehtaab Sawhney , Mark Sellke , Gregory Valiant