[hnkain]

https://blog.paulhankin.net

I don't think everyone should read it, because it's quite technical. There's articles on mathematics, game-theory, and computer science.

The highlight (in my opinion) is a series of articles on Fibonacci numbers, with relatively novel content: https://blog.paulhankin.net/fibonacci/, https://blog.paulhankin.net/fibonacci2/, https://blog.paulhankin.net/fibonacci_doubling/

The first two in particular, are quite fun I think, playing with short integer-only computation of the Fibonacci numbers (and also the n-acci numbers).

[hnkain]

If you like programming puzzles, I also recommend trying to write the littlemancomputer programs listed on this blog entry: https://blog.paulhankin.net/littlemancomputer/

They are fun in the same way as TIS-100 is fun, and especially the last couple (generate primes, sort input) are interestingly difficult.

Instructions and description of the machine on wikipedia: https://en.wikipedia.org/wiki/Little_man_computer

Online emulator: https://blog.paulhankin.net/lmc/lmc.html

[note: the blog post contains some minor hints, and solutions in links]