We have completed another year of Numberphile videos. I watched much fewer of these episodes when they were first published. I got a lot more discerning as time went on. Only watching those that piqued my interest either through the title or thumbnail image. You miss so many great videos that way. The reason why I like this project is that I am watching some for the first time.

Hopefully people who stumble on this project will go back through the archives and see these gems.

### SERIES TABLE OF CONTENTS

- A Retrospective by Year
- The First Year
- 1
^{st}Anniversary - 2
^{nd}Anniversary - 3
^{rd}Anniversary - 4
^{th}Anniversary - 5
^{th}Anniversary - 6
^{th}Anniversary - 7
^{th}Anniversary - 8
^{th}Anniversary - 9
^{th }Anniversary - 10
^{th}Anniversary - 11
^{th}Anniversary

## The Playlist

Here is the playlist of the third anniversary videos. They are in order of publication date. The personal annotations are numbered by the video’s position in the playlist for easy reference. You can view this playlist on YouTube.

There are 71 videos and the total playlist time is about 10 hours and 49 minutes.

## Personal Annotations

(9) Perfect Number Proof

I’ve never understood why Mersenne Primes would be more interesting than any other prime. They are primes in the form 2^n - 1. They are one less than a power of two.

One of the reasons they get so much attention is because of the race to find new ones powered by people’s computer cycles. You can download a program and maybe find the next Mersenne Prime! The current largest prime (as of 2018) was found through the Great International Mersenne Prime Search.

Well, this video reveals why they are important. Every Mersenne Prime is related to a perfect number. Matt Parker illustrates the proof here.

(13) (14) Rock, Paper, Scissors with Hannah Fry

These are the first viedeos with Hannah Fry. She is one of the more popular math communicators. I love her books. She has only gone on to greater things. She is (as of 2024) the President of the Institute of Mathematics and its Applications. There is such as strong tradition of supporting and communicating about math in the UK. I want to start something like that here and I’m trying to put on a math comm conference.

(15) How Random is a coin toss?

It was surprising to find this video. I’ve read about this research as recently as last year. It was based on a paper from the professor featured here, Persi Diaconis. This video is from 2015, but this reseracb by Diaconis goes back to 2007.

(23) The Bridges to Fermat’s Last Theorem

This is one of the rare occassions that Brady interviews someone who has gone down in mathematical history. This time with Ken Ribet whose work was instrumental in the proof of Fermat’s Last Theorem. This video gives so much background on how that proof came together.

What I like about it though is the mention of algebraic geometry which was also important for the proof. It uses Deformation theory in Galois representations by Barry Mazur. I had heard that algebraic geometry was used but I didn’t know how. Now I know.

(39) Numbers With Meaning

This is high up on my list of favorite Numberphile videos of all time. My background is in cognitive psychology. Anything related to the brain is my jam. This is an interesting look at how the brain processes numbers. With the most interesting insight being that we also think of numbers autobiographically. Some numbers have more meaning than others.

(42) The man with 1,000 Klein Bottles UNDER his house

I love any video with Cliff Stoll. I am enthusiastic about math. There are people who have tried to rain on my parade. But, it doesn’t hurt anyone and it makes me happy. So, I’m happy every time that I see Cliff because it is a reminder that it is okay. I don’t think that I’m alone at all anymore.

(46) Why 1980 was a great year to be born… but 2184 will be better

This video caught my interest because it is relevant to 2025. Which at this time is next year. I wonder if Matt will remember this video then. Or what he has planned for his special birthday. I thought it was pretty special when I turned 42.

(60) The Infinitesimal Monad

I thought this was an interesting video in the series on infinities. This time about something infintiesimally small. In the next video, James Grime takes about infinitesimals in relation to calculus. Even if they are no longer used because we have limits. It is an interesting part of math history still.

(71) The Uncracked Problem with 33

This is the Numberphile video that inspired a proof. The sum of three cubes for the number 33 was found in 2019. Laregly due to the fact that this video was seen by the mathematcian who found it, Andrew R. Booker. Brady would go on to interview the people who found 42 and another solution for 3. All these solutions were found using computers.

That is the end of this year of Numberphile. Can you believe that we are four years in now. There are still many more years to go. We aren’t even half way through yet! Numberphile had its twelfth anniversary in 2023. Something that I will cover in January of 2025. Click the links below to continue the series.