Welcome to the 145th Carnival of Mathematics, hosted here at The Aperiodical.

If you’re not familiar with the Carnival of Mathematics, it’s a monthly blog post, hosted on some kind volunteer’s maths blog, rounding up their favourite mathematical blog posts (and submissions they’ve received through our form) from the past month, ish. If you think you’d like to host one on your blog, simply drop an email to katie@aperiodical.com and we can find an upcoming month you can do. On to the Carnival!

Hi! I’m Dani Poveda. This is my first post here on The Aperiodical. I’m from Spain, and I’m not a mathematician (I’d love to be one, though). I’m currently studying a Spanish equivalent to HNC in Computer Networking. I’d like to share with you some of my inquiries about some numbers. In this case, about triangular square numbers.

I’ll start at the beginning.

I’ve always loved maths, but I wasn’t aware of the number of YouTube maths channels there were. During the months of February and March 2016, I started following some of them (Brady Haran’s Numberphile, James Grime and Matt Parker among others). On July 13th, Matt published the shortest maths video he has ever made:

Maybe it’s a short video, but it got me truly mired in those numbers, as I’ve loved them since I read The Number Devil when I was 8. I only needed some pens, some paper, my calculator (Casio fx-570ES) and if I needed extra help, my laptop to write some code. And I had that quite near me, as I had just got home from tutoring high school students in maths.

I’ll start explaining now how I focused on this puzzle trying to figure out a solution.

Here’s our annual round-up of what’s happening in sums/thinking at this year’s Manchester Science Festival. If you’re local, or will be in the area around 20th-30th October, here’s our picks of the finest number-based shows, talks and events.

I’d have written it as $r = 1 – \theta$, myself, but even then it’s not much of a heart. However, that’s pretty much my biggest gripe about this episode, the penultimate in series 2 of Samuel Hansen’s one-of-a-kind mathematics podcast, Relatively Prime.

Episode 7 is subtitled “Dating in the mathematical domain”, and looks at the maths involved in dating and relationships, and begins with some of the comments Sam’s dating profile received from non-mathematicians. Now, denizens of the dating world: Samuel has many flaws and failings; picking on the fact that he’s a mathematician seems a little arbitrary and unfair, like deciding not to vote for Donald Trump because you don’t like his tie. I have this unfamiliar sensation. Could it be… surely not? It appears that I feel a little sorry for Samuel. Don’t tell him, ok?

Breaking news! On 19th January 2016, the Great Internet Mersenne Prime Search discovered a new largest prime number – we know 49 Mersenne primes, the largest of which is now $2^{74207281}-1$, a number containing over 22 million digits and full of primey goodness.

Maths – as teachers are fond of telling anyone who’ll listen – is everywhere. In this difficult second episode of the difficult second series of Relatively Prime, Samuel Hansen shows us a few important places where it can be a help: at the petrol pump, at the birthday party, in the car park and at the bar — or rather, in deciding whether to go.

To celebrate the year end, as well as our daily Advent Calendar posts, we’re also running a little competition – last year we did a pun competition, and this year it’s something a bit more crafty – well, it’s a knitting competition in which the knitting is optional.