A lattice point in the coordinate plane with origin O is called invisible if the segment OA contains a lattice point other than O and A. Let L be a positive integer. Show that there exists a square with side length L and sides parallel to the coordinate axes, such that all points in the square are invisible.
(In reply to
some progress by Steven Lord)
As per below -
"6) I have seen somewhere before this "comb" of lines (of multiples) used to search for primes (where new primes would lie off of any lines of multiples of known primes.) "
Edited on February 5, 2021, 9:51 pm
re: some progress
