Category Archives: primes

Factorization diagram posters!

I’ve finally gotten around to making a nice factorization diagram poster: You can buy high-quality prints from Imagekind. (If you order soon you should have them before Christmas! =) I’m really quite happy with imagekind, the print quality is fantastic … Continue reading

Posted in arithmetic, counting, geometry, number theory, pattern, pictures, primes | Tagged , , | 7 Comments

Animated Sieve of Eratosthenes

Here’s something I made yesterday! (Note, I strongly suggest watching it fullscreen, in HD if you have the bandwidth for it.) Can you figure out what’s going on? The source code for the animation is here; I was inspired by … Continue reading

Posted in arithmetic, counting, pattern, pictures, primes, video | | 12 Comments

Factorization diagram cards: help?

The other day I got a lovely email from Malke Rosenfeld thanking me for creating factorization diagrams and linking me to her blog post about “factor dominoes”: she printed out some factorization diagrams, glued them to cardstock, and used the … Continue reading

Posted in arithmetic, pictures, primes | Tagged , , , | 2 Comments

Mersenne primes and the Lucas-Lehmer test

Mersenne numbers, named after Marin Mersenne, are numbers of the form . The first few Mersenne numbers are therefore , , , , , and so on. Mersenne numbers come up all the time in computer science (for example, is … Continue reading

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More factorization diagrams

My post on factorization diagrams from a month ago turned out to be (unexpectedly) quite popular! I got ten times as many hits as usual the day it was published, and since then quite a few other people have created … Continue reading

Posted in arithmetic, links, pictures, primes, programming, recursion | Tagged , , | 15 Comments

Factorization diagrams

In an idle moment a while ago I wrote a program to generate "factorization diagrams". Here’s 700: It’s easy to see (I hope), just by looking at the arrangement of dots, that there are in total. Here’s how I did … Continue reading

Posted in arithmetic, pictures, primes, programming, recursion | Tagged , , | 72 Comments

Book Review: The Enigma of the Spiral Waves

The Enigma of the Spiral Waves (Secrets of Creation Volume 2)words by Matthew Watkins, pictures by Matt Tweed Matthew Watkins and Matt Tweed have done it again! I previously wrote a (very positive) review of Volume I—this book is just … Continue reading

Posted in books, open problems, primes, review | Tagged , , | 1 Comment