论文标题
素数和斐波那契数的最大共同分数
Greatest common divisors of shifted primes and Fibonacci numbers
论文作者
论文摘要
令$(f_n)$为fibonacci数字的顺序,对于每个正整数$ k $,令$ \ nathcal {p} _k $是Primes $ p $的集合,使得$ \ gcd(p -1,f_1,f_ {p -1})= k $。我们证明存在$ \ Mathcal {p} _k)的相对密度$ \ text {r}(\ Mathcal {p} _k)$,并且存在$ \ text {r}(\ nathcal {p} _k)$的公式,以绝对收敛的系列为单位。此外,我们给出一个有效的标准,以确定给定的$ k $是否满足$ \ text {r}(\ Mathcal {p} _K)> 0 $,并且我们为此类$ k $的集合功能提供了上下界限。作为结果的应用,我们为某些正整数$ n $ $ \ gcd(n,f_n)$的整数的计数函数提供了新的证明。我们的证明比Leonetti和Sanna给出的先前的证明更为基础,后者依赖于Cibre and Rouse的结果。
Let $(F_n)$ be the sequence of Fibonacci numbers and, for each positive integer $k$, let $\mathcal{P}_k$ be the set of primes $p$ such that $\gcd(p - 1, F_{p - 1}) = k$. We prove that the relative density $\text{r}(\mathcal{P}_k)$ of $\mathcal{P}_k$ exists, and we give a formula for $\text{r}(\mathcal{P}_k)$ in terms of an absolutely convergent series. Furthermore, we give an effective criterion to establish if a given $k$ satisfies $\text{r}(\mathcal{P}_k) > 0$, and we provide upper and lower bounds for the counting function of the set of such $k$'s. As an application of our results, we give a new proof of a lower bound for the counting function of the set of integers of the form $\gcd(n, F_n)$, for some positive integer $n$. Our proof is more elementary than the previous one given by Leonetti and Sanna, which relies on a result of Cubre and Rouse.