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Unusual prime number competition results

Author Robin Sloan offered a simple competition:

give me a prime number of your choosing. I’ll send books to the five people who choose the lowest unique prime numbers. So, if you pick 2 but seven other people pick 2, no book for you. If you pick 3 and no one else picks 3, you get a book.

Which number would you pick?

The primes people chose, including the five winners, and more background information are given in a blog post The Penumbra primes.

6 Responses to “Unusual prime number competition results”

  1. Peter Rowlett Peter Rowlett

    @Paul: I thought almost the same thing when I saw the link! A set of rules is only as good as its weakest link, and you’ll almost certainly be low and unique (but high enough that it’s not obvious whether it’s a prime).

  2. Avatar garycroft

    I say 89, because the number of primes between 1 and 89^2 is exactly 1000, as amplified upon here:


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