MathDB
Does there Exist?

Source: ToT - 2001 Fall Junior A-Level #1

August 17, 2011
greatest common divisornumber theory unsolvednumber theory

Problem Statement

Do there exist postive integers a1<a2<<a100a_1<a_2<\cdots<a_{100} such that for 2k1002\le k\le100 the greatest common divisor of ak1a_{k-1} and aka_k is greater than the greatest common divisor of aka_k and ak+1a_{k+1}?