This year I am planning a quite interesting Halloween day. I have already started searching for inspiration for my classroom and I am extremely excited for everything. I will write a blog post about this very soon, stay tuned. All this excitement of mine has transformed into another campaign on Teespring called Vampire Numbers.

If you thought that vampires have absolutely nothing do with maths, well a small girl from Romania (the land of Dracula) will tell you otherwise. The definition is not that hard to understand:

In mathematics, a vampire number (or true vampire number) is a composite natural number v, with an even number of digits n, that can be factored into two integers x and y each with n/2 digits and not both with trailing zeroes, where v contains precisely all the digits from x and from y, in any order, counting multiplicity. x and y are called the fangs.

Even though I have not found many things about when these numbers first appeared and who came with the idea to call them “vampire numbers” and not something else, but I find them quite interesting. If you want to generate the first 25 vampire numbers (or more if you a total computer science fan), I totally recommend you take a look at the article Vampire Numbers from Rosettacode. If you want to find out more about these numbers, I recommend you watch the following video:

If I convinced you that these are great numbers, take a look at my designs from the Vampire Numbers campaign:

Hope you enjoyed this post and that you are excited for Halloween. Have a great week. You can find me on Facebook, Tumblr, Google+, Twitter  and Instagram. I will try to post there as often as possible.

Don’t forget that maths is everywhere! Enjoy!