Carnival of Mathematics 140

The next issue of the Carnival of Mathematics, rounding up blog posts from the month of October/November, and compiled by Tom, is now online at Mathematics and Coding.

The Carnival rounds up maths blog posts from all over the internet, including some from our own Aperiodical. See our Carnival of Mathematics page for more information.

Maths Journals for an engaged Sixth Former

Maths legend Colin Wright posed this question on Twitter:

It led to a flurry of interesting replies, and here’s some of them.

Education bits: new PBS maths series, National Numeracy game, etc.

I’m not normally interested in education stuff, but we’ve had a flurry of emails from various people telling us about their projects, and I’ve got nothing else to do today, so I thought I’d round them up.

A more equitable statement of the jealous husbands puzzle

Every time I use the jealous husbands river crossing problem, I prefix it with a waffly apology about its formulation. You’ll see what I mean; here’s a standard statement of the puzzle:

Three married couples want to cross a river in a boat that is capable of holding only two people at a time, with the constraint that no woman can be in the presence of another man unless her (jealous) husband is also present. How should they cross the river with the least amount of rowing?

I’m planning to use this again next week. It’s a nice puzzle, good for exercises in problem-solving, particularly for Pólya’s “introduce suitable notation”. I wondered if there could be a better way to formulate the puzzle – one that isn’t so poorly stated in terms of gender equality and sexuality.

Apéryodical: Roger Apéry’s Mathematical Story

This is a guest post by mathematician and maths communicator Ben Sparks.

Roger Apéry: 14th November 1916 – 18th December 1994

100 years ago (on 14th November) was born a Frenchman called Roger Apéry. He died in 1994, is buried in Paris, and upon his tombstone is the cryptic inscription:

$1 + \frac{1}{8} + \frac{1}{27} +\frac{1}{64} + \cdots \neq \frac{p}{q}$

Apéry’s gravestone – Image from St. Andrews MacTutor Archive

Roger Apéry – Image from St. Andrews MacTutor Archive

The centenary of Roger Apéry’s birth is an appropriate time to unpack something of this mathematical story.

Puzzlebomb – November 2016

Puzzlebomb is a monthly puzzle compendium. Issue 59 of Puzzlebomb, for November 2016, can be found here:

The solutions to Issue 59 will be posted at the same time as issue 60.

Previous issues of Puzzlebomb, and their solutions, can be found at Puzzlebomb.co.uk.

The magic number 25641

Reader of the site Bhaskar Hari Phadke has written in to tell us this fun fact about the number $25641$. It’s easier to show than to describe, so here goes:

\begin{align}
25641 \times \color{blue}{1} \times 4 &= \color{blue}{1}02564 \\
25641 \times \color{blue}{2} \times 4 &= \color{blue}{2}05128 \\
25641 \times \color{blue}{3} \times 4 &= \color{blue}{3}07692 \\
25641 \times \color{blue}{4} \times 4 &= \color{blue}{4}10256 \\
25641 \times \color{blue}{5} \times 4 &= \color{blue}{5}12820 \\
25641 \times \color{blue}{6} \times 4 &= \color{blue}{6}15384 \\
25641 \times \color{blue}{7} \times 4 &= \color{blue}{7}17948 \\
25641 \times \color{blue}{8} \times 4 &= \color{blue}{8}20512 \\
25641 \times \color{blue}{9} \times 4 &= \color{blue}{9}23076
\end{align}

A good one to challenge a young person with.

I did a little bit of Sloanewhacking and found a couple of sequences containing $25641$ which almost, but don’t quite, describe this property. So, semi-spoiler warning: you might enjoy A256005 and A218857. I’d like to come up with the ‘magic number’ which looks the least like it’ll have this property – any ideas?