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The incredible palindromic hat-trick

Would you like to see something AMAZING?

I’ve made another one of my interactive online maths doodads. You should have a go at it right now. It doesn’t require any effort on your part, other than coming up with a positive integer.

Exactly how bad is the 13 times table?

Let’s recite the $13$ times table. Pay attention to the first digit of each number:

\begin{array}{l} \color{blue}13, \\ \color{blue}26, \\ \color{blue}39, \\ \color{blue}52 \end{array}

What happened to $\color{blue}4$‽

A while ago I was working through the $13$ times table for some boring reason, and I was in the kind of mood to find it really quite vexing that the first digits don’t go $1,2,3,4$. Furthermore, $400 \div 13 \approx 31$, so it takes a long time before you see a 4 at all, and that seemed really unfair.

The OEIS now contains 300,000 integer sequences

The Online Encyclopedia of Integer Sequences just keeps on growing: at the end of last month it added its 300,000th entry. Especially round entry numbers are set aside for particularly nice sequences to mark the passing of major milestones in the encyclopedia’s size; this time, we have four nice sequences starting at A300000. These were sequences that were originally submitted with indexes in the high 200,000s but were bumped up to get the attention associated with passing this milestone.

Are you more likely to be killed by a meteor or to win the lottery?

This tweet from the QI Elves popped up on my Twitter timeline:

In the account’s usual citationless factoid style, the Elves state that you’re more likely to be crushed by a meteor than to win the jackpot on the lottery.

The replies to this tweet were mainly along the lines of this one from my internet acquaintance Chris Mingay:

Yeah, why don’t we hear about people being squished by interplanetary rocks all the time? I’d tune in to that!

Donald Knuth’s 2017 Christmas lecture: “A Conjecture That Had To Be True”

Every year, Donald Knuth gives a Christmas lecture at Stanford.

This year, he wanted to talk about a conjecture he’s recently investigated.

It’s just over an hour long. Sit down with a warm drink and enjoy some interesting recreational maths from the master.

Scenes at a maths conference

We’re all trying to combat the stereotypes of mathematicians: we try our best to make our work accessible to the public; we wear clean clothes and make eye contact; some of us even had the good sense to be female. But sometimes, the woolly-headed mathematician of legend materialises in his pure form.

Here, in his own words, are a few things that happened at a conference recently attended by one of my friends.

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