Nice blog (in appearance, contents and implementation). See https://archive.casouri.cat/note/2018/blog-in-org-mode-revisited/index.html for an update.
An interesting idea for entering mathematical symbols is presented on https://archive.casouri.cat/note/2020/insert-math-symbol-in-emacs/index.html

Neat description of Reed-Solomon error codes and two simple error-correction algorithms, implemented in Python.
Found on https://planet.scheme.org/ via the article
https://jeremykun.com/2020/09/11/searching-for-rh-counterexamples-setting-up-pytest/

PCG is a family of simple fast space-efficient statistically good algorithms for random number generation. Unlike many general-purpose RNGs, they are also hard to predict.

Interesting software, such as
unifdef selectively removes C preprocessor conditionals. My version of this program now shipped by all the BSDs (including Mac OS X) and is used by the Linux kernel build system.
regpg safely stores server secrets using gpg, so you can keep them in version control.
picoro - tiny coroutine implementations in pure C. I wrote an accompanying article, coroutines in 20 lines of standard C.
Counting the days - tiny routines for converting Gregorian dates into linear counts, like Julian day numbers or Unix time_t. The date of the count - a small routine for converting linear day counts into Gregorian dates.
https://dotat.at/@/2016-04-22-synergy-vs-xmodmap-fight.html Why you can't use xmodmap to change how Synergy handles modifier keys
https://dotat.at/@/2023-05-26-whence-time.html Where does my computer get the time from?
https://dotat.at/@/2023-08-04-unix69.html a neat keyboard map
https://dotat.at/@/2024-01-29-four-point-egg.html construct an egg shape with straightedge and compass
His log of links, https://dotat.at/:/ which I found on the TUHS mailing list is also worth reading. He explains a bit about this log on http://dotat.at/.

Joe Marshall's non-lisp blog. Lisp/Scheme are the subject of his other blog,
Abstract Heresies, Unorthodox opinions on computer science and programming. http://funcall.blogspot.com/

Collection of interesting papers, including the famous MIT HAKMEM http://home.pipeline.com/~hbaker1/hakmem/hakmem.html
Lisp, garbage collection, modular arithmetic and more.

Apart from the blog, there are technical notes https://www.johndcook.com/blog/writing/ and on-line calculators https://www.johndcook.com/blog/online-calculators/
As an example, see Camp-Paulson normal approximation to the binomial distribution https://www.johndcook.com/blog/camp_paulson/
The articles https://www.johndcook.com/blog/2024/04/01/more-laguerre-images/ and
https://www.johndcook.com/blog/2024/03/22/laguerres-root-finding-method/ demonstrate the basins of attraction for Laguerre's root-finding method.
https://www.johndcook.com/blog/2018/11/24/spheroid-distance/ should be useful for azel.
https://www.johndcook.com/blog/2020/02/08/arenstorf-orbit/ shows a periodic solution to the restricted 3-body problem.
https://www.johndcook.com/blog/2022/11/14/simultaneous-root-finding/ describes the Durand-Kerner polynomial root finding method.
https://www.johndcook.com/blog/2022/11/01/kepler-newton/ discusses solving Kepler's equation

TODO: https://www.johndcook.com/blog/2022/10/30/arctan-k-tan-t/ states "This plot looks similar to the plot of true anomaly for a highly elliptical orbit. I’m sure they’re related, but I haven’t worked out exactly how."

https://www.johndcook.com/blog/2022/10/21/math-origins/ explains V.I. Arnolds comment
"All mathematics is divided into three parts: cryptography (paid for by CIA, KGB and the like), hydrodynamics (supported by manufacturers of atomic submarines), and celestial mechanics (financed by military and other institutions dealing with missiles, such as NASA)."

https://www.johndcook.com/blog/2018/09/24/riemann-hypothesis-the-fine-structure-constant-and-the-todd-function/ is about  Sir Michael Atiyah's incorrect proof of Riemann's hypothesis, the article https://rjlipton.com/2018/09/26/reading-into-atiyahs-proof/ is an interesting read. (I had bookmarked this entry on Wed Sep 26 15:51:47 2018 and put it here 2024-04-03.)

The article https://www.johndcook.com/non_central_chi_square.pdf sounds interesting:
John D. Cook Upper bounds on non-central chi-squared tails and truncated normal moments (2010). UT MD Anderson Cancer Center Department of Biostatistics Working Paper Series. Working Paper 62.
Abstract. We show that moments of the truncated normal distribution provide upper bounds on the tails of the non-central chi-squared distribution, then develop upper bounds for the former.

Recommended on MoHP.

There a number of interesting articles such as
- The Mystery of the Grazing Goat  http://www.mathpages.com/home/kmath074/kmath074.htm
- On The Solution of the Cubic Equation  http://www.mathpages.com/home/kmath444/kmath444.htm
- Infinite grid of resistors, ...