this post was submitted on 03 Sep 2025
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xkcd #3137: Cursed Number

Title text:

Another group of mathematicians is working to put an upper bound on the number, although everyone keeps begging them to stop.

Transcript:

Transcript will show once it’s been added to explainxkcd.com

Source: https://xkcd.com/3137/

explainxkcd for #3137

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[–] badcommandorfilename@lemmy.world 40 points 11 months ago

print(uuid())

[–] palordrolap@fedia.io 31 points 11 months ago (2 children)

Felt like noodling a little with some numbers. I have a nice candidate. 22301. Pretty small, right? ~~It's prime.~~ That's not troubling to most anyone's sanity. Edit: one should check one's silly code more carefully before madly pretending to be mad on the Internet. It is not prime. But the intermediate numbers still are.

There's something that can be done to that number four times (but no more) which results in a prime each time and the fourth step results in a 70 digit number that I may have looked at slightly tOo LoNnNg.

Edit 2: Attempt at redemption for the math if not the joke: Start with 5497949 which is prime, and you can do the thing four times and get a prime each time. The last one has 108 digits and, no word of a lie, starts 6969...

Imaginary bonus points for guessing what the heck the operation / something is.b

[–] Audalin@lemmy.world 23 points 11 months ago (1 children)

But 22301 isn't prime? It's 29*769.

[–] palordrolap@fedia.io 33 points 11 months ago (1 children)

Well, this is embarrassing. This is what I get for mathing after midnight.

[–] porl@lemmy.world 8 points 11 months ago (1 children)

The true number messed you up so much you can't recall it any more.

[–] scathliath@lemmy.dbzer0.com 2 points 11 months ago

Can confirm, it stole my lunch money when I tried to see it, then gaslit me and told me my fiancee did. Truly a cursed number.

[–] jaupsinluggies@feddit.uk 8 points 11 months ago (1 children)

If you divide it by itself and add one, you can do that infinitely many times and get a prime every time. Works for all the primes.

[–] four@lemmy.zip 27 points 11 months ago (1 children)

A moment of silence for all those who sacrificed themselves in the name of science

[–] ZoteTheMighty@lemmy.zip 10 points 11 months ago

Actually, this isn't useful, so we still let it be called "math".

[–] IndustryStandard@lemmy.world 14 points 11 months ago (2 children)

The cursed number is pi. Everyone who tries to fully read it dies. This is why we shortened it to 3.14.

[–] UnrepententProcrastinator@lemmy.ca 5 points 11 months ago (2 children)
[–] whoisearth@lemmy.ca 4 points 11 months ago

Meh close enoigh

[–] Cocodapuf@lemmy.world 2 points 11 months ago

I like 22/7

[–] DarkCloud@lemmy.world 9 points 11 months ago

Sounds like those stupid Rationalist cult groups who spend their time coming up with AI fantasies, and claim some thought-experiments are so powerful they'll ruin your mind - real immature stuff. Deserves to be lampooned like this.

[–] nialv7@lemmy.world 6 points 11 months ago (1 children)

If a number is long enough human won't be able to perceive it all at once, so in fact there are only finite number of cases we need to check.

[–] Jankatarch@lemmy.world 3 points 11 months ago

Human will run out of memory when reading the number, in fact.

[–] ripcord@lemmy.world 6 points 11 months ago (1 children)

Sounds like the seed of an SCP.

[–] Swedneck@discuss.tchncs.de 1 points 11 months ago

peep the horror

[–] tisktisk@piefed.social 4 points 11 months ago (3 children)

I'm confused, what is this new lower bound specifically?

[–] finalarbiter@lemmy.dbzer0.com 6 points 11 months ago

The number that makes people go insane is bigger than 2.6*10^21^, or 2,600,000,000,000,000,000,000

[–] pressanykeynow@lemmy.world 4 points 11 months ago

Works as intended then.

[–] Dasus@lemmy.world 4 points 11 months ago

Sure there's quite a lot of them to choose from, but for instance USPS tracking numbers are 22-digit numbers.

[–] ksigley@lemmy.world 3 points 11 months ago

There really is an xkcd for everything.

[–] ShinkanTrain@lemmy.ml 2 points 11 months ago

This is why they invented notation. Just to be safe