### π calculated to 31 trillion digits

This Pi Day, Emma Haruka Iwao has announced calculation of $\pi$ to $\pi \times 10^{13} = 31,\!415,\!926,\!535,\!897$ digits, exceeding the previous record of 22 trillion digits set in November 2016.

This used y-cruncher, running Chudnovky’s algorithm. Chudnovky’s algorithm is $\mathcal{O}(n(\log n)^3)$, making each record more impressive. In a blog post, Emma writes about the benefits of using a cloud cluster, saying the calculation ran on a virtual machine cluster, using

25 nodes for 111.8 days, or 2,795 machine-days (7.6 machine-years), during which time Google Cloud performed thousands of live migrations uninterrupted and with no impact on the calculation process.

Ways to access the digits and fun related bits and bobs are outlined in the blog post.

### 33 can be written as the sum of three cubes

It was an open question whether 33 could be written as the sum of three cubes. Thanks to Andrew R. Booker, it now isn’t.

\begin{array}{c} (8866128975287528)^3 \\ + \\(-8778405442862239)^3 \\ + \\(-2736111468807040)^3 \\ = \\ 33\end{array}

Today’s Google Doodle (visit google.com to see it, or if you miss today, you can find it in their archive) celebrates Russian mathematician Olga Ladyzhenskaya. In recognition of her 97th birthday, the Doodle includes the Navier-Stokes equations, of which Ladyzhenskaya provided the first rigorous proofs of convergence using a finite-difference method.

### Doodling for π day

It’s that time of year again – 3.14 (March 14th), a.k.a π day, is just around the corner, and if you want to do something fun on the day, now’s the time to plan it. One nice way to celebrate this brilliant infinite string of digits is by creating π-inspired art, and we’ve spotted a couple of relevant links if that’s your jam.

• Maths learning organisation (and Carnival of Mathematics stalwarts) Ganit Charcha are running a competition for schools in India, challenging them to ‘Doodle for π‘ – students should take inspiration from a mathematical concept, and create a doodle/image to submit. The competition invites creativity and imagination, and runs until 12th March.
• If you’re not in India, you can still use π as inspiration for artworks – Think Maths speaker and Aperiodical Math-off contestant Zoe Griffiths has put together a set of ideas for how to use π to create beautiful pictures, to decorate your home, school or office.

### One Mathematically Gifted and Black person every day this Black History Month

February is Black History Month in the USA, so the website Mathematically Gifted and Black is honouring a different black mathematician each day in February, for the third year.

### #Noethember: a retrospective

Last November, under the banner of #Noethember, we helped organise an international drawing challenge themed around mathematician Emmy Noether. The project resulted in a huge number of drawings and a warm feeling among those who participated. For 30 days, people across Twitter shared their sketches illustrating facts about Noether’s life and work.

### Sir Michael Atiyah has died

Over the weekend we heard the sad news that mathematician Sir Michael Atiyah has passed away on 11th January. One of the few mathematicians to have been awarded both a Fields medal and an Abel prize, Atiyah leaves behind an extensive mathematical legacy and will be missed by many.

A tribute to former President of the Royal Society Sir Michael Atiyah OM FRS (1929 – 2019), on the Royal Society website

Mathematician Sir Michael Atiyah dies aged 89, at BBC News

Michael Atiyah, Mathematician in Newton’s Footsteps, Dies at 89 at the New York Times