A story of mathematical play.
Home page: www.3blue1brown.com
Brought to you by you: 3b1b.co/spiral-thanks

Based on this Math Stack Exchange post:
math.stackexchange.com/questions/885879/meaning-of-rays-in-polar-plot-of-prime-numbers/885894

Want to learn more about rational approximations? See this Mathologer video.
youtu.be/CaasbfdJdJg

Also, if you havent heard of Ulam Spirals, you may enjoy this Numberphile video:
youtu.be/iFuR97YcSLM

Dirichlets paper:
arxiv.org/pdf/0808.1408.pdf

Important error correction: In the video, I say that Dirichlet showed that the primes are equally distributed among allowable residue classes, but this is not historically accurate. (By «allowable», here, I mean a residue class whose elements are coprime to the modulus, as described in the video). What he actually showed is that the sum of the reciprocals of all primes in a given allowable residue class diverges, which proves that there are infinitely many primes in such a sequence.

Dirichlet observed this equal distribution numerically and noted this in his paper, but it wasnt until decades later that this fact was properly proved, as it required building on some of the work of Riemann in his famous 1859 paper. If Im not mistaken, I think it wasnt until Vallée Poussin in (1899), with a version of the prime number theorem for residue classes like this, but I could be wrong there.

In many ways, this was a very silly error for me to have let through. It is true that this result was proven with heavy use of complex analysis, and in fact, its in a complex analysis lecture that I remember first learning about it. But of course, this would have to have happened after Dirichlet because it would have to have happened after Riemann!

My apologies for the mistake. If you notice factual errors in videos that are not already mentioned in the videos description or pinned comment, dont hesitate to let me know.

— These animations are largely made using manim, a scrappy open-source python library: github.com/3b1b/manim

If you want to check it out, I feel compelled to warn you that its not the most well-documented tool, and it has many other quirks you might expect in a library someone wrote with only their own use in mind.

Music by Vincent Rubinetti.
Download the music on Bandcamp:
vincerubinetti.bandcamp.com/album/the-music-of-3blue1brown

Stream the music on Spotify:
open.spotify.com/album/1dVyjwS8FBqXhRunaG5W5u

If you want to contribute translated subtitles or to help review those that have already been made by others and need approval, you can click the gear icon in the video and go to subtitles/cc, then «add subtitles/cc». I really appreciate those who do this, as it helps make the lessons accessible to more people.

— 3blue1brown is a channel about animating math, in all senses of the word animate. And you know the drill with YouTube, if you want to stay posted on new videos, subscribe: 3b1b.co/subscribe

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