I’m a big fan of recreational mathematics so when I was watching the first episode of the 2nd season of Patience to kick off my weekend, my spider senses started tingling when Patience mentioned vampire numbers as something “used all the time in computer programming”.
As a developer, that sounded weird to me as I had never heard of a such thing but lo and behold, it’s a real thing. Wikipedia says:
In recreational mathematics, a vampire number (or true vampire number) is a composite natural number with an even number of digits, that can be factored into two natural numbers each with half as many digits as the original number, where the two factors contain precisely all the digits of the original number, in any order, counting multiplicity. The two factors cannot both have trailing zeroes. The first vampire number is 1260 = 21 × 60.
I couldn’t find anything about them being used in programming though but it’s so cool to learn about new number concepts like this.
Interestingly enough, the number in the show (90831) is not a vampire number because it has five digits. Such a weird mistake to make when picking up such a specific and niche thing. She even explains the concept of vampire number correctly immediately after calling 90831 as one.