Here are a few of the stories that we didn’t get round to covering in depth this month.
Turing’s Sunflowers Project – results
Manchester Science Festival’s mass-participation maths/gardening project, Turing’s Sunflowers, ran in 2012 and invited members of the public to grow their own sunflowers, and then photograph or bring in the seed heads so a group of mathematicians could study them. The aim was to determine whether Fibonacci numbers occur in the seed spirals – this has previously been observed, but no large-scale study like this has ever been undertaken. This carries on the work Alan Turing did before he died.
The results of the research are now published – a paper has been published in the Royal Society’s Open Science journal, and the findings indicate that while Fibonacci numbers do often occur, other types of numbers also crop up, including Lucas numbers and other similarly defined number sequences.
Long-time Aperiodical muse David Cushing has made a bet with us that he can give us an interesting post every Friday for the next ten weeks. Every week that he sends a post, we buy him a bar of chocolate. Every week that he doesn’t send us a post, he buys us a bar of chocolate. For his first trick, David is going to do some unnatural things with the natural numbers.
The greatest common divisor (gcd) of two or more integers is the greatest integer that evenly divides those integers. For example, the gcd of $8$ and $12$ is $4$ (usually written as $\gcd(8,12)=4$). Two integers are called coprime (or “relatively prime”) if their gcd is equal to $1$.
A reasonable question to ask is,
Given two randomly chosen integers $a$ and $b$, what is the probability that $\gcd(a,b)=1$?