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# Monthly Archives: January 2013

## New “Chaos” videos from the makers of “Dimensions”

I just got an email from Jos Leys, one of the creators of the Dimensions video series (which I wrote about previously), announcing that they have released another video series, this time about Chaos, at http://www.chaos-math.org/en. I haven’t had a … Continue reading

## What I Do, Part I: Programming languages (Up-Goer 5 edition)

“Splasho” has has created an online text editor which checks to make sure you use only the 1000 most common English words, inspired by this recent XKCD comic. Over the past few weeks, many scientists have taken up the challenge … Continue reading

## Introduction to Mathematical Thinking

Keith Devlin is going to be offering another instance of his online course, Introduction to Mathematical Thinking, starting on March 4. The idea is to serve as a bridge between high school mathematics— which focuses on solving specific types of … Continue reading

## 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

Posted in arithmetic, computation, famous numbers, iteration, modular arithmetic, number theory, primes
Tagged lehmer, lucas, Mersenne, prime, test
3 Comments

## The Steinhaus-Johnson-Trotter algorithm

In a previous post I posed the question: is there a way to list the permutations of in such a way that any two adjacent permutations are related by just a single swap of adjacent numbers? (Just for fun, let’s … Continue reading

Posted in combinatorics, pattern, solutions
Tagged algorithm, change, permutations, ringing, SJT, swap
9 Comments