# Carnival of Mathematics 204

It’s that time again – I’m back writing the Carnival of Mathematics, and we’re now on number 204 (where does the time go?)! You may remember when I wrote number 190, but for those unfamiliar with the Carnival, it is a monthly roundup of Mathematical blogging/video making/podcasting/activities, coordinated by The Aperiodical.

As is tradition, last time I started with facts about the number $190$, and now it’s the turn of $204$. Starting with the very basics $204 = {2}^{2} \times 3 \times 17$. $204$ is actually a refactorable number, which means it is divisible by the count of it’s divisors. $204$ is the sum of twin primes (namely $101$ and $103$) AND it’s square is also the sum of twin primes: $41616 = 20807 + 20809$. A final primal fact about $204$: ${204}^{n} + 1$ is prime for $n$ equal to any of the digits of $204$..

Some other fun mathematical fact about the number: it is a nonagonal number (if you’re not sure what this is, think about how you might extend triangle and sqaure numbers to other polygons). $204 = {1}^{2} + {2}^{2} + {3}^{2} + {4}^{2} + {5}^{2} + {6}^{2} + {7}^{2} + {8}^{2}$ making it a square pyramidal number.

There are $204$ ways of placing three non-attacking chess-queens on a $5\times 5$ board. There are also $204$ hands at least as good as a straight flush in a poker deck with a single wild joker. $204$ is also the HTTP status code that conveys a request has been fulfilled successfully with no further content to be sent in response.

But that’s enough about $204$. I want to kick off this month’s mathematical roundup by talking The Aperiodical itself, as on the 25th April, The Aperiodical turned $10$ years old! They celebrated with some rather skillfully decorated cakes, and a round up of their top posts from the past 10 years.

As with any other month, The Aperiodical has provided us with a lot of quality mathematical content this month, so I won’t list all their blog posts, but would like to share Katie Steckles’ review of Math Games with Bad Drawings. I met with Katie to test out some of the games beforehand, and would thoroughly recommend the book. Have a read to see what Katie thought!

In another lovely throwback to my first time hosting the Carnival, I came across this lovely blog post by Sophie, AKA fractalkitty. Sophia hosted the 191st Carnival of Mathematics, the one after mine, and hence this is now the second time I have linked to her blog in these posts! In this blog post, Sophia introduces us to $73,034,632$ haiku and proves, both through her poetry and her accompanying art, that Maths can be beautiful and creative.

And now I’d like to move from blogs to dogs. Namely, Skylab, Matt Parket’s Labrador. I’m both a dog nerd, and a Maths nerd so I was always going to love Matt’s video about registering dog names with the American Kennel Club, and the best numbering system to use (hint: it’s not Roman Numerals, or at least not as you know them). This also brought back some fun memories of trying to get my dog registered with The Kennel Club in the UK so that we could do agility competitions (he was a rescue and definitely not a pure breed!). Unfortunately, the name “Dipstick Spydog Trotter” was rejected though so we had to settle with “Prewash Friendly Playtime”.

Segueing on to other things that made me laugh, this blog post explains one of my favourite Maths jokes. One of my university lecturers made the mistake once of asking “Do you all understand?” and I’ll let you work out the rest…

Colin has been at it again with another “Ask Uncle Colin” post, where he answers questions he has been sent. This time, it’s the turn of a functions question and not only does Colin explain his thought process really well, it’s also a great puzzle to have a go at yourself first!

A quick podcast roundup now: Mathematical Objects released a couple topologically equivalent podcasts: one about the superegg, with Hannah Fry; and one about the hairy ball. A Podcast of Unneccessary Detail released four (!!) episodes this month, and Tim Harford has created more episodes of More of Less for the BBC (with my personal highlights being Substituation and simpligying: how to better explain numbers, and Did tea-drinking cut deaths in the Industrial Revolution).

April marks the birthday of Dorothy Lewis Bernstein, the first femal president of the Mathematics Association of America. I love learning more about Mathematicians I’m less familiar with, so enjoyed this blog post about her.

Women in Mathematics and Physics were a hot topic of conversation in April after Katharine Birbalsingh commented that she thought girls at her school were put of studying Physics A Level by the “hard Maths”. I could write a whole blog post on my thoughts about these comments (needless to say I disagree and think they were unhelpful things to have been said) but the Carnival is not the place for such a rant so I will instead direct you to this tweet by Jess Wade, and recommend that you also read some of the replies to it. One this I will say though, is that whilst I disagree with Katharine, she does not deserve the abuse she’s getting for these comments, and the comments should also be put in the context of her being asked what is arguably an unfair question in the first place.

I want to end on a cheery note though, and what better thing than Chalkdust. You may know my now that I am on the editorial team for Chalkdust Magazine. This month (on April 1st no less), Chalkdust was featured on BBC1’s Have I Got News For You (Series 63, Episode 1). It was an incredibly exciting moment for us, and lovely to be able to share Maths with a primetime TV audience!

Speaking of lovely things, it’s been a pleasure to host the 190th Carnival of Mathematics. The next is hosted by Rob at Rob Eby’s Math Blog so head on over there next month to check it out!