Infinitely many primes in arithmetic progressions

In 2025, Joan Arenillas worked as a final bachelor's project on the elementary proofs for certain cases of Dirichlet's theorem. In this link you can find an automatic proof generator for these elementary proofs.

Modular calculator

Here you can find A modular calculator. It can compute safe primes (primes p such that p - 1 is twice a prime) using Miller-Rabin's test, and do efficient arithmetic modulo any integer. In particular, it can be used to perform the Diffie-Hellman key agreement protocol.

Illustration of the Eratostenes' sieve

You can see a dynamical animation of how Eratostenes' sieve works. Play with it here.

Ilustration for Euclid's algorithm

An illustration of Euclid's algorithm to obtain Bézout's identity.