Chatting to YuloTomorrow on Twitter made me look into Project Euler, and it's kind of taken over my head.

For anyone who doesn't know Leonhard Euler was an 18th century Swiss mathematician who, basically, invented maths. OK, that's an overstatement, but to quote his wikipedia page. "So many things were named after Euler, that after a while some things were named after the next person who discovered it." Kind of like when one kid gets all the questions right, and then the teacher says "ok, you've answered enough times, let's let someone else answer"...

The thing is, though, that a lot of his maths is REALLY esoteric. The toffs back then used to love sending each other problems by post. "I was thinking, one could not possible derive the nth semi-aquatic demi-prime with an even number of digits, of which one of them is a seven"... And then the recipient would beaver away to find an answer. Turns out half the mathematicians in Europe did this to poor Leonhard, and he ended up solving pretty much everything they threw at him... But the problems are so esoteric that most people have never heard of them.. Some are to do with combinatorics, some prime numbers, others are to do with fractions and irrational numbers. Chances are you used some of his stuff at school, but weren't told where it came from.

So, Project Euler is a website with hundreds of bizarre esoteric maths questions, with difficulty ratings, and you have to solve them. How you do it is up to you. The site's geared towards mathematicians and coders with enough algorithmic or maths knowledge to know where to look for information to solve problems.

I started out just brute-forcing everything, and my development knowledge let me get all the way past about #50 without needing to do much research, but as the slog towards #100 has continued, the number of problems whose esoteric nature make them truly bizarre are forcing me to do more and more research. How to partition numbers, how to generate pythagorean triples, how to factorize large numbers quickly, etc etc.

It's definitely not for everyone, but it's damn satisfying when you get the right answer! :)