MathDB
Constructing numbers with large prime divisors

Source: 2023 Macedonian Team Selection Test P1

May 21, 2023
number theory

Problem Statement

Let s(n)s(n) denote the smallest prime divisor and d(n)d(n) denote the number of positive divisors of a positive integer n>1n>1. Is it possible to choose 20232023 positive integers a1,a2,...,a2023a_{1},a_{2},...,a_{2023} with a1<a21<...<a20232022a_{1}<a_{2}-1<...<a_{2023}-2022 such that for all k=1,...,2022k=1,...,2022 we have d(ak+1ak1)>2023kd(a_{k+1}-a_{k}-1)>2023^{k} and s(ak+1ak)>2023ks(a_{k+1}-a_{k}) > 2023^{k}?
Proposed by Nikola Velov