Remember, remember,

The fourteenth of March.

While the previous number of *All Squared* failed to achieve topicality by appearing several weeks after the event it was about, this time we’ve hit the nail bang on the head with a podcast all about π day… *on π day!*

We chatted to Festival of the Spoken Nerd’s Steve Mould about remembering π – how much can you memorise; how much *should* you memorise; and if you really insist on memorising it, what’s the best way to do it?

Here are some links to the things we referred to in the podcast, along with some bonus extras:

- The number of this episode is 3, which is exactly π if you don’t think very hard when you read the Bible
- A chronology of the computation of π
- Epic π quest sets 10 trillion digit record, at
*New Scientist* - Download 4 million digits of π
- “Using pi calculated out to only 39 decimal places would allow one to compute the circumference of the entire universe to the accuracy of less than the diameter of a hydrogen atom.“
- The π Code - π in base 26 ≈ D.DRSQLOL
- 33,333 digits of π in base-(the 1000 most common words in the English language)
- Japanese breaks pi memory record on BBC News (in which “Conventionally, 3.14159 is used as pi.”)
- Japanese man claims new record for memorising ‘pi’ at the Daily Mail (in which “It is usually written out to a maximum of three decimal places, as 3.141, in math textbooks.”)
- Akira Haraguchi
- The official world record for memorising π is held by Chao Lu of China, who memorised 67,890 decimal digits.
- Kolmogorov complexity (Steve had the definition right – it measures just the length of the
*description*of the thing, and doesn’t measure the resources required to interpret that description) - Normal number
- Find your birthday in π
- Find any string of digits in π
- Michael Hogg’s method of memorising 100 digits of π
- Joshua Foer: Moonwalking with Einstein - a talk about a book about memory
- Irrational sonnets (where the stanzas have 3,1,4,1,5 lines) in French, or in English
- A mnemonic for π which is also a pangram, in French
- Previously on The Aperiodical: Random walks on π, a marvellous visualisation of the digits of π.
- Circular reasoning: who first proved that $C/d$ is a constant? - a historical essay by David Richeson.
- While Steve was chatting to us, his collaborator Matt Parker was measuring π with pies for
*Numberphile*.

Steve Mould has his fingers in, if you’ll excuse one final pun, many pies. Here are some links to some of his projects you might find interesting:

Podcast: Play in new window | Download

I’ve just noticed that in the “pi in base 26″ link, A = 0. While starting from zero is the correct way to count, in this case setting A = 1 means Z can stand for ‘zero’. Opportunity: missed.

Towards the end, Katie might be remembering Not A Wake by Mike Keith, which is a mnemonic for the first ten thousand digits (using ten letter words for zero). He has a web site full of similar madness: http://www.cadaeic.net/index.html