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"1 is non-prime by definition."

dammit!


It's mainly due to the Fundamental Theorem of Arithmetic (aka unique prime factorization) - https://en.wikipedia.org/wiki/Fundamental_theorem_of_arithme...


However this was not settled surprisingly late.

I have seen tables of prime counts produced in the 1950s and 1960s that specified whether they counted 1 as a prime, and some did count it.


"The history of the primality of one: a selection of sources" (https://cs.uwaterloo.ca/journals/JIS/VOL15/Caldwell2/cald6.h..., via https://primes.utm.edu/):

"The way mathematicians have viewed the number one (unity, the monad) has changed throughout the years. Most of the early Greeks did not view one as a number, but rather as the origin, or generator, of number. Around the time of Simon Stevin (1548-1620), one (and zero) were first widely viewed as numbers. This created a period of confusion about whether or not the number one was prime. In this dynamic survey, we collect a cornucopia of sources which deal directly with the "question what is the smallest prime?" The goal is to create a source book for studying the history of the definition of prime, especially as applied to the number one."


Still the case for the natural numbers (with 0 instead of 1). Though perhaps more obvious why you would choose one or the other there.

Going through school I'd be told 1 was/not prime differently by different teachers. Always seemed pretty arbitrary to me; like 'They' ought just to decide!

What we seem to be hearing here is that They had, just another classic case of this information taking 50 years to filter down the education system.. (I wonder how many planets they teach there as being in our solar system?)


>(I wonder how many planets they teach there as being in our solar system?)

Your comment got me to look up the number of objects considered planets over the years, this has ranged from 5-23. Data since 1543 is available here: https://dx.doi.org/10.1038%2Fscientificamerican0107-34

For fun I did a linear regression of year vs # planets and found that the while the slope was 1.8 planets/century, this was not significantly different from zero. The evidence appears to be consistent with a constant number of planets.


I froze when I saw 1, and ended up going the same way you did. That one feels cheap. :P


Yeah, that ended my run at 22 correct answers. Pretty annoying. I knew it was non-prime by definition, but I had no idea whether this quiz was aware of that, so I just made a quick gut decision.


I would not recommend game dev on twitch, example: handmade hero, awesome project, super great guy, but it is nearly impossible to follow what is going on.



Well, that's in the Confirmed Hoaxes section of that page. :)

The N1 rocket (USSR's workhorse for their Lunar space program in the '60s) never worked well. Chief Engineer Korolev (the Russian counterpart to Wernher von Braun) dying in the mid-60s certainly didn't help. The project suffered from "financial malnutrition" for a long time, due to political infighting within the top levels of the Communist Party.

The N1 test launches were all rushed, improvised affairs that failed, sometimes spectacularly. https://en.wikipedia.org/wiki/Largest_artificial_non-nuclear...

The way the project operated was, basically, "we don't have enough money to run horizontal burn tests properly, so we'll do it live, with a full-scale vertical launch". The results were what you would expect.

Main point is, the Russians didn't have a properly working vehicle in the '60s to reach Moon orbit. They were starting to figure out the issues with the N1 towards the end of the decade, but then Armstrong set foot on Luna and the rest is history. The N1 was cancelled quietly in the mid-70s.


So did they actually do the egg eggsperiment with this micro lattice material?


Hmm.. That let me think.. "Eggsperiment"!


I stopped using groupon when the hostess slipped us a different menu when she asked us if we had a groupon to use.


I've had this experience a few times and every single time it was mentioned on the Groupon, I actually checked out the menu before hand, and bought or refused the deal there and then. This isn't really unique, you buy a specific deal so you get that deal's menu, Groupon rarely sells some kind of carte blanche 20% discount card on whatever the company offers which seems to be what you were expecting.

I've also had Groupon redeem me for stuff that I had no right to in the TOS but was morally sensible to do.

There are quite a few things I criticise Groupon for but they've always been pretty transparent about their deals and willing to right any wrongs in my personal experience.


It does read a little too passive aggressive.


Amazing, thank you for sharing!


It is up, but I think instead it should go meta: There should be a new section describing how his own wikipedia article came about.


Yes, a delicious twist of irony.


Love Waterfall Glen!


I always enjoyed his blogs, I wonder why he doesn't write anymore.


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