Elementary Papers at ArXiv Inspired by this question, at MO i am asking this question.
Can anyone list some elementary articles at ArXiv which can be understood by High-School/Undergrad Students. I am asking this because, i would like to see some interesting papers and articles to learn something new. If the paper is very much advanced then its of no use to me since i haven't learnt enough Math. I have been searching around for past two hours and i couldn't find a single paper which i could comprehend. Article which i would like to see:-


*

*Interesting proofs of some Elementary number Theory results.

*Interesting identity involving Infinite series.

*Interesting articles in Basic Abstract Algebra ( concerning Groups and Rings.)

*Your favorite article. ( Make sure its elementary enough!)
The best example of what type of articles i am looking for can be found in the answer given by Bill here:


*

*Characterizing continuous functions based on the graph of the function
This is an interesting article. I really enjoyed reading it since i could understand it.
 A: A similar paper to Yuval's answer, which is also quite elementary, is Doyle (and Conway)'s Division by Three. I don't think it requires any advanced knowledge, and is rather interesting.  
A: Depending on your tastes, there's a nice paper called Recounting the Rationals, by Calkin and Wilf. (Get it here, here, here or here.) I mention it as answer to your question because there's a blog post about it which says

If you are just learning to read math papers, or you think you might like to learn to read them, [this paper] would be a good place to start. It is serious research mathematics, but elementary. It is very short. The result is very elegant. The proofs are straightforward. The techniques used are typical and widely applicable; there is no weird ad-hockery. The discussion in the paper is sure to inspire you to tinker around with it more on your own. All sorts of nice things turn up. […] Check it out.

You should read the paper directly, but if you get stuck or would like more detail, there's also a six-part series about it (! 1, 2, 3, 4, 5, 6), Wikipedia, articles for further reading, etc.
A: I thought that What is special about the divisors of 24? was creative and fairly approachable.
A: It is in the nature of modern mathematics to be fairly technical and therefore inaccessible to a novice, but the category "math.HO' at the arxiv sometimes contains papers readable by a non-expert.  For example, I just looked through the recent papers in that category and found an interesting piece on "unity and disunity of mathematics" and there are many others.
A: That's a bit of a stretch, but the beautiful paper Seven Trees in One by Andreas Blass (which has a faulty ArXiv version) is perhaps possible to understand up to section 4 (which is exactly where my understanding stops). The first three sections are not really difficult, even though they mention some abstract non-sense (which you can skip), some enumerative combinatorics (which you can also skip), and some really basic definitions in abstract algebra, which are unfortunately too "basic" to include in a normal course; but all you need to know about them is how to calculate within them. You also need to know some very basic set theory (mainly $\aleph_0^2 = \aleph_0$).
A: If you like pizza, you might wanna look at: http://arxiv.org/abs/0812.2870
A: I stumbled upon This one:
http://arxiv.org/pdf/1312.3839.pdf
which might fit the bill. The title is:
"On the antiderivative of inverse functions"  and at least parts of it is elementary.      
A: I enjoyed this one very much: How to compute $\sum 1/n^2$ by solving triangles
A: Sometime in the near future I plan on posting a paper in the General Mathematics section that may be what you're looking for, but for the time being you can find the paper here.
