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# Tag Archives: primes

## 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
Tagged diagrams, Eratosthenes, primes, sieve, visualization
12 Comments

## Fun with repunit divisors

In honor of today’s date (11/11/11), here’s a fun little problem (and some follow-up problems) I’ve seen posed in a few places (for example, here is a very similar problem). If I recall correctly, it was also a problem on … Continue reading

Posted in arithmetic, challenges, modular arithmetic, number theory, primes
Tagged divisors, primes, repunit
16 Comments

## Prime Time in Haskell

In a recent blog post, Patrick Vennebush of Math Jokes 4 Mathy Folks noted that 2011 can be expressed as a sum of consecutive prime numbers, and challenged his readers to work out how. He also posed a couple further … Continue reading

Posted in arithmetic, number theory, primes, programming
Tagged consecutive, Haskell, primes, sum
8 Comments