Hidden Graph

There is an unweighted, undirected hidden graph. You are given an integer range from LLL to RRR. There are total ofR−L+1R-L+1R−L+1 nodes numbered from LLL to RRR. Two nodes U,VU,VU,V have an edge between them if the GCD(U,V)GCD(U, V)GCD(U,V) is greater than 111.

This is a companion discussion topic for the original entry at https://toph.co/p/hidden-graph