MathDB

Even number of prime divisors

Source: Kvant Magazine No. 4 2022 M2696

March 8, 2023

Kvantnumber theory

Problem Statement

Does there exist a sequence of natural numbers

a_1,a_2,\ldots

such that the number

a_i+a_j

has an even number of different prime divisors for any two different natural indices

i{}

and

j{}

?
From the folklore