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arXiv 1010.2489math.NTmath.CO
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关于同余的三个定理的证明

Proof of three conjectures on congruences

Hao Pan, Zhi-Wei Sun

摘要:

本文证明了三个关于中心二项式系数或Lucas序列的同余的定理。令$p$是奇素数,令$a$是正整数。我们表明,如果$p\equiv 1\pmod{4}$或$a>1$,则$$ \sum_{k=0}^{\lfloor\frac34p^a\rfloor}\binom{-1/2}k\equiv\left(\frac{2}{p^a}\right)\pmod{p^2}, $$,其中$(-)$表示Jacobi符号。这证实了第二作者的一个猜想。我们还证实了R. Tauraso通过证明$$\sum_{k=1}^{p-1}\frac{L_k}{k^2}\equiv0\pmod{p}\quad {\rm provided}\ \ p>5,$$,其中卢卡斯数$L_0,L_1,L_2,\ldots$由$L_0=2,\ L_1=1$和$L_{n+1}=L_n+L_{n-1}\ (n=1,2,3,\ldots)$定义。我们的第三个定理指出,如果$p\not=5$,那么我们可以通过以下方式确定$F_{p^a-(\frac{p^a}5)}$ mod $p^3$:$$\sum_{k=0}^{p^a-1}(-1)^k\binom{2k}k\equiv\left(\frac{p^a}5\right)\left(1-2F_{p^a-(\frac{p^a}5)}\right)\ \pmod{p^3},$$这在Sun和Tauraso的一篇论文中作为猜想出现在2010年。

英文摘要:

In this paper we prove three conjectures on congruences involving central binomial coefficients or Lucas sequences. Let $p$ be an odd prime and let $a$ be a positive integer. We show that if $p\equiv 1\pmod{4}$ or $a>1$ then $$ \sum_{k=0}^{\lfloor\frac34p^a\rfloor}\binom{-1/2}k\equiv\left(\frac{2}{p^a}\right)\pmod{p^2}, $$ where $(-)$ denotes the Jacobi symbol. This confirms a conjecture of the second author. We also confirm a conjecture of R. Tauraso by showing that $$\sum_{k=1}^{p-1}\frac{L_k}{k^2}\equiv0\pmod{p}\quad {\rm provided}\ \ p>5,$$ where the Lucas numbers $L_0,L_1,L_2,\ldots$ are defined by $L_0=2,\ L_1=1$ and $L_{n+1}=L_n+L_{n-1}\ (n=1,2,3,\ldots)$. Our third theorem states that if $p\not=5$ then we can determine $F_{p^a-(\frac{p^a}5)}$ mod $p^3$ in the following way: $$\sum_{k=0}^{p^a-1}(-1)^k\binom{2k}k\equiv\left(\frac{p^a}5\right)\left(1-2F_{p^a-(\frac{p^a}5)}\right)\ \pmod{p^3},$$ which appeared as a conjecture in a paper of Sun and Tauraso in 2010.

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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