MathDB
sequence of N consecutive , when product of 2 of them is divided by other's sum

Source: St. Petersburg 2016 9.7

May 1, 2019
Integer sequenceSequencenumber theorynumber theory with sequences

Problem Statement

A sequence of NN consecutive positive integers is called good if it is possible to choose two of these numbers so that their product is divisible by the sum of the other Nāˆ’2N-2 numbers. For which NN do there exist infinitely many good sequences?