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arXiv 0909.5648math.NTmath.CO
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二项式系数、Catalan数和Lucas数

Binomial coefficients, Catalan numbers and Lucas quotients

Zhi-Wei Sun

摘要:

设$p$是奇素数,$a,m$是具有$a>0$和$m \not\equiv0\pmod p$的整数.在本文中,我们确定$d=0,1$的$\sum_{k=0}^{p^a-1}\binom{2k}{k+d}/m^k$ mod $p^2$;例如,$$\sum_{k=0}^{p^a-1}\frac{\binom{2k}k}{m^k}\equiv\left(\frac{m^2-4m}{p^a}\right)+\left(\frac{m^2-4m}{p^{a-1}}\right)u_{p-(\frac{m^2-4m}{p})}\pmod{p^2},$$,其中$(-)$是Jacobi符号,$\{u_n\}_{n\geqslant0}$是由$u_0=0$,$u_1=1$和$u_{n+1}=(m-2)u_n-u_{n-1}$给出的Lucas序列,用于$n=1,2,3,\ldots$。作为一个应用,我们确定了对任意整数$r$的$\sum_{0<k<p^a,\, k\equiv r\pmod{p-1}}C_k$模$p^2$,其中$C_k$表示Catalan数$\binom{2k}k/(k+1)$。我们还提出了一些相关的建议。

英文摘要:

Let $p$ be an odd prime and let $a,m$ be integers with $a>0$ and $m \not\equiv0\pmod p$. In this paper we determine $\sum_{k=0}^{p^a-1}\binom{2k}{k+d}/m^k$ mod $p^2$ for $d=0,1$; for example, $$\sum_{k=0}^{p^a-1}\frac{\binom{2k}k}{m^k}\equiv\left(\frac{m^2-4m}{p^a}\right)+\left(\frac{m^2-4m}{p^{a-1}}\right)u_{p-(\frac{m^2-4m}{p})}\pmod{p^2},$$ where $(-)$ is the Jacobi symbol, and $\{u_n\}_{n\geqslant0}$ is the Lucas sequence given by $u_0=0$, $u_1=1$ and $u_{n+1}=(m-2)u_n-u_{n-1}$ for $n=1,2,3,\ldots$. As an application, we determine $\sum_{0<k<p^a,\, k\equiv r\pmod{p-1}}C_k$ modulo $p^2$ for any integer $r$, where $C_k$ denotes the Catalan number $\binom{2k}k/(k+1)$. We also pose some related conjectures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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