According to their own site, Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.
I have been tackling these problems at random intervals since 2011, while I was still studying my Bachelor's in Computer Science and Mathematics.
Note that there might be problems for which I have no code, since in the beginning I solved them in Java but unfortunately I lost the code.
Furthermore, since many problems might benefit from specific functions (such as efficient prime sieve generation or probabilistic primality tests), I have compiled the ones I consider relevant enough in functions.py.
Note that it is possible to simply look for the solutions online and submit them to cheat a score in the website.