Is there a resource which is good questions on quadratic

[matqkks]

I am looking for some interesting questions on quadratic residues. Anyone know of any resources for an elementary number theory course. I am not looking for drill problems to practice but some important results.

 

[fresh_42]

Starting with quadratic residue, I arrived at close-packing of spheres within 3 clicks on Wikipedia:
quadratic residue - quadratic reciprocity - cubic reciprocity - sphere packing.
Another example as for many number theoretic results is cryptography: quadratic-rest-problem.
I'm sure there are a lot more results which are probably more sophisticated, too.

 

[jedishrfu]

I found these via google search:

http://www2.gcc.edu/dept/math/faculty/BancroftED/teaching/handouts/quadratic_reciprocity.pdf

https://www.maths.tcd.ie/pub/Maths/Courseware/NumberTheory/QuadraticResidues.pdf

http://math453spring2009.wikidot.com/lecture-18

http://sites.millersville.edu/bikenaga/number-theory/quadratic-residues/quadratic-residues.html