Problems
Blog posts with problems to get your brain going! You get a new problem every fortnight and the solutions are published later.
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You may notice some problems are missing... I'm still migrating articles from my old blog.
Can you prove that there are arbitrarily many primes in arbitrarily big intervals?
This simple problem is an example of a very interesting phenomenon: if you have a large enough "universe" to consider, even randomly picked parts exhibit structured properties.
