Zobrazeno 1 - 10
of 59
pro vyhledávání: '"CAO Hui-qin"'
Publikováno v:
工程科学学报, Vol 37, Iss 5, Pp 621-625 (2015)
Oxide dispersion strengthening(ODS) copper has the characteristics of both high strength and high conductivity. The porosity is an important factor influencing the electrical conductivity. 0.9Al2O3/Cu powder was compacted by a high velocity compactio
Externí odkaz:
https://doaj.org/article/5165b747c17040ba923adb6b8c21c9ba
Publikováno v:
Int. J. Number Theory 16(2020), no. 5, 981--1003
In this paper we establish some congruences involving the Ap\'ery numbers $\beta_{n}=\sum_{k=0}^{n}\binom{n}{k}^2\binom{n+k}{k}$ $(n=0,1,2,\ldots)$. For example, we show that $$\sum_{k=0}^{n-1}(11k^2+13k+4)\beta_k\equiv0\pmod{2n^2}$$ for any positive
Externí odkaz:
http://arxiv.org/abs/1812.10351
Akademický článek
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Autor:
Cao, Hui-Qin, Pan, Hao
For the Schr\"oder number $$ S_n=\sum_{k=0}^n\binom{n}k\binom{n+k}k\frac1{k+1}, $$ we prove that $$ S_{n+2^\alpha}\equiv S_{n}+2^{\alpha+1}\pmod{2^{\alpha+2}}, $$ where $n\geq 1$ and $\alpha\geq 1$.
Externí odkaz:
http://arxiv.org/abs/1512.06310
Publikováno v:
Electron. J. Combin. 21(2014), no. 1, #P1.13, 1-25
Let $A$ be a finite set of integers. We show that if $k$ is a prime power or a product of two distinct primes then $$|A+k\cdot A|\geq(k+1)|A|-\lceil k(k+2)/4\rceil$$ provided $|A|\geq (k-1)^{2}k!$, where $A+k\cdot A=\{a+kb:\ a,b\in A\}$. We also esta
Externí odkaz:
http://arxiv.org/abs/1011.5438
Autor:
Cao, Hui-Qin, Pan, Hao
We prove several congruences for trinomial coefficients.
Externí odkaz:
http://arxiv.org/abs/1006.3025
Autor:
Cao, Hui-Qin, Sun, Zhi-Wei
Publikováno v:
Colloq. Math. 139(2015), no.1, 127-136
Binomial coefficients and central trinomial coefficients play important roles in combinatorics. Let $p>3$ be a prime. We show that $$T_{p-1}\equiv\left(\frac p3\right)3^{p-1}\ \pmod{p^2},$$ where the central trinomial coefficient $T_n$ is the constan
Externí odkaz:
http://arxiv.org/abs/1006.3069
Autor:
Cao, Hui-Qin, Pan, Hao
We confirm several conjectures of Guo, Jouhet and Zeng concerning the factors of alternative binomials sums.
Comment: This is a preliminary draft
Comment: This is a preliminary draft
Externí odkaz:
http://arxiv.org/abs/0903.3767
Autor:
Cao, Hui-Qin, Pan, Hao
In the paper, we generalize some congruences of Lehmer for general composite numbers.
Comment: 7 pages
Comment: 7 pages
Externí odkaz:
http://arxiv.org/abs/math/0608565
Autor:
Cao, Hui-Qin, Pan, Hao
In this paper, we establish some Fleck-Weisman type and Davis-Sun type congruences for the Stirling numbers and the Eulerian numbers.
Comment: 13 pages
Comment: 13 pages
Externí odkaz:
http://arxiv.org/abs/math/0608564