Duff’s rule says that a nanocentury is about π seconds. Assuming a year is 365.25 days, there are 3,155,760,000 seconds in a century. So a nanocentury, one billionth of a century, is 3.15576 seconds, roughly π seconds. This odd fact…

Duff’s rule says that a nanocentury is about π seconds. Assuming a year is 365.25 days, there are 3,155,760,000 seconds in a century. So a nanocentury, one billionth of a century, is 3.15576 seconds, roughly π seconds. This odd fact…

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Before Google, there was googol, the number 10^100, written as a 1 followed by 100 zeroes. There are about 4 × 10^79 atoms in the universe. (Here’s a derivation of that number.) You could bump that number up a little…

Ten previous blog posts on music. Odd meters Music in 5/4 time Blue Rondo à la Turk March in 7/4 time Music and computers Typesetting music in LaTeX with LilyPond Windows XP and Ubuntu start-up music Music and math Opening…

Emacs has quite a sophisticated scientific calculator. Like many other things in Emacs, it is both powerful and idiosyncratic.

Math Fun Facts is a large collection of very short mathematical articles, each less than a page, maintained by my friend Francis Su. These articles are a great resource for teachers looking for interesting examples to spice up a class.…

Google Google street view Antarctica Google’s alternative to JPEG Statistics Three-quarter truths: correlation is not causation Bounds for non-central chi-square tails Miscellaneous Math lessons for locavores Victorian submarines How ink is made

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The fastest ways to test whether a number is prime have some small probability of being wrong. Said another way, it’s easier to tell whether a number is “probably” prime than to tell with certainty that it’s prime. This post…

If you’ve ever seen Casablanca, you’ve heard the song As Time Goes By, but only the chorus. You must remember this A kiss is just a kiss, a sigh is just a sigh. The fundamental things apply As time goes…

Matthias Vallentin posted a comment on my post about a math/CS cheat sheet to say that he’s been working on a probability and statistics cheat sheet. Looks great, though at 24 pages it stretches the definition of “cheat sheet” even…

On June 30, 2010 Donald Knuth announced iTeX, the successor to TeX. His announcement was an extended parody of much of what people recommend as the “right” way to develop software. TeX has been extremely successful. The vast majority of…

Here’s something called a theoretical computer science cheat sheet. I don’t know whether I agree with the name, but it’s a nice cheat sheet. The first two pages of the cheat sheet have to do with sums, combinatorics, and recurrence…

Music Classical sacred music Music in 5/4 time Math The history and future of special functions Carnival of Mathematics blog Computing Running Facebook’s servers How to write a Lisp interpreter in Python Productivity The myth of laser focus Podcast on…

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