Project P is a combinatorial problems page I started in Februray 2015.
Porject P focuses on enumerative combinatorics, i.e., counting. At least one problem is posted every month. No matter you are in high school or graduate school, welcome to solve them. They are challenging and open. We highly encourage people to sumbit their work and also people could submit their own problems.
Click here to visit Project P.
Project P webpages have lots of formulas. If formulas are not shown correctly, please refresh the webpage.
HtmlPuzzles is a puzzle-solving webpage, based on knowledge of Html.
Click here to solve puzzles!