Generalized Sierpiński numbers
Tom 174 / 2023
                    
                    
                        Colloquium Mathematicum 174 (2023), 191-201                    
                                        
                        MSC: Primary 11A07; Secondary 11B25, 11N13.                    
                                        
                        DOI: 10.4064/cm9156-9-2023                    
                                            
                            Opublikowany online: 17 November 2023                        
                                    
                                                Streszczenie
A Sierpiński number is a positive odd integer $k$ such that $k \cdot 2^n + 1$ is composite for all positive integers $n$. Fix an integer $A$ with $2 \le A$. We show that there exists a positive odd integer $k$ such that $k\cdot a^n + 1$ is composite for all integers $a \in [2, A]$ and all $n \in \mathbb {Z}^+$.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            