It's where people get together to have a discussion around a set piece of reading. In this case the reading is of a textbook, and the discussion is intended to help everyone understand the material.
That's what dictionary.com says, and that's true in some places, but in other places "guys" is definitely gendered.
Imagine a group of cishet men saying : "I'm off to the strip club to see a bunch of guys taking their clothes off and dancing in a provocative manner."
Does that seem reasonable? If not, then the term "guys" is gendered.
On top of that, most of the women I know feel that "guys" is a term that excludes them. That's enough for me to avoid using it.
In searching about an obscure fact concerning languages I found Paul Graham's essay "Beating the Averages"[0] I found it interesting, and started to read some of the other essays. As a quick hack I then drew a diagram of the obvious connections between them[1]. Similarly, I then used a PageRank-style ranking of the essays[2].
I sent the results to Paul Graham, who said I should submit them to HN, of which I'd never heard. I did so, and they pretty much sunk without trace, as do so many of my submissions. Even so, I read some more, and stayed for a while.
Is this a handle you use all over? A lot of times people will say "contact me at handle at gmail" or some such thing. I'm curious to know whether HN handles are used all over, or are special use for HN.
I guess I should comment here, but I don't have much to add. Most of the questions that arise naturally about how this was done, and about primes in general, have already been asked and answered.
Still, given my username I should add something ...
So if the size was prime x prime then the fact that the number of bits is a semi-prime tells you the size of the image, even if all you have is a stream of digits. Then the "noise" at the end will tell you what the least significant bits are, and hence you get an image without very much ambiguity.
More discussion: https://news.ycombinator.com/item?id=26329791
A few other comments: https://news.ycombinator.com/item?id=26339162
Steven Galbraith's criticism: https://twitter.com/EllipticKiwi/status/1367322432571240450