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Re:A New Largest-Known Prime Number by userbinator on Saturday December 22, 2018 @02:35AM (#18739480)
We would write the number out for you, but it would fill up thousands of pages, give or take, and look like this gigantic zip file.

It's ironic to see that 11MB file being called "gigantic" in this day and age; many web pages are now unfortunately much larger, and the page of the article itself transfers at least 1MB of data.

Re:A New Largest-Known Prime Number by carlob on Saturday December 22, 2018 @05:01AM (#18739926)
Then it's probably in decimal form. The binary representation should compress much better :)
Re:A New Largest-Known Prime Number by paulddraper on Saturday December 22, 2018 @12:39PM (#18741542)
Explanation: A Mersenne prime is (2^n)-1 so in binary that's n 1s.
Re:A New Largest-Known Prime Number by dvh on Saturday December 22, 2018 @05:24AM (#18739973)
Any number N in base (N) is written as 1
Re:A New Largest-Known Prime Number by carlob on Saturday December 22, 2018 @05:27AM (#18739987)
no it's 10
Re:A New Largest-Known Prime Number by SomeHacker44 on Saturday December 22, 2018 @08:15PM (#18743699)
Typical programmer. Off by zero as always.
Re:A New Largest-Known Prime Number by anoncoward111 on Saturday December 22, 2018 @03:03AM (#18739553)
Unironically this. NPR even has a subdomain for text only (text.npr.org), but only select articles are ported because reasons.

A thorough joke.

Re:A New Largest-Known Prime Number by delhanty on Friday December 21, 2018 @07:40PM (#18738061)
Read this and wondered, what estimates are there on the density of the Mersenne primes as n grows?

Google told me that, surprisingly, it's not even known that they are infinite!

I found this nice page on the Wagstaff Mersenne Conjecture:

https://primes.utm.edu/mersenne/heuristic.html

Re:A New Largest-Known Prime Number by ryacko on Friday December 21, 2018 @09:05PM (#18738429)
Possibly the only civilian use of quantum computing, an interesting decade is ahead.
Re:A New Largest-Known Prime Number by scythe on Saturday December 22, 2018 @12:14AM (#18739062)
Primality testing is actually much easier than integer factorization thanks to Fermat's "little" theorem. Methods based on this theorem, including the Lucas-Lehmer test for Mersenne primes, can identify prime numbers on classical computers in polynomial time. However, factorization is not possible with this method.
Re:A New Largest-Known Prime Number by chris_st on Saturday December 22, 2018 @09:25AM (#18740674)
That's okay, hardly anyone needs to factor prime numbers :-)
Re:A New Largest-Known Prime Number by fluxty on Friday December 21, 2018 @11:01PM (#18738834)
I used to be into this stuff in college--we were obsessed with the idea of generating very large or else very large numbers of odd numbers, such as weird numbers or untouchable numbers. I was into HPC and writing programs that run on clusters, and this gave me some good practice.

We eventually realized that no one really cared about the numbers we felt confident we could find--now Mersenne primes, though, people really care about those, but they're extraordinarily difficult to find. Always a cool day to see a new one.

Re:A New Largest-Known Prime Number by AlexCoventry on Sunday December 23, 2018 @01:49PM (#18747631)
It's not clear to me that anyone really cares about Mersenne primes, either, which is not to detract from this cool result in any way.
Re:A New Largest-Known Prime Number by heyjudy on Friday December 21, 2018 @09:07PM (#18738439)
Mersenne primes in binary are all 1's with length n.

PS: I remember scheduling Prime95 to run on lab computers at work (a nuclear engineering shop) after-hours, c. 1998.

Re:A New Largest-Known Prime Number by NKosmatos on Saturday December 22, 2018 @02:53AM (#18739519)
The official press release from GIMPS: https://www.mersenne.org/primes/?press=M82589933
Re:A New Largest-Known Prime Number by eximius on Friday December 21, 2018 @09:32PM (#18738555)
Anyone know what primality test they use? Miller-Rabin for testing then something deterministic for verification?
Re:A New Largest-Known Prime Number by ehsankia on Friday December 21, 2018 @10:06PM (#18738679)
Re:A New Largest-Known Prime Number by man-and-laptop on Saturday December 22, 2018 @06:01AM (#18740065)
It would be nice if this were used as the PoW problem for a blockchain. Since the Mersenne Primes are rare, the PoW problem shouldn't be to find new Mersenne Primes directly, but something that could make indirect progress on that. Also the blockchain should solve an actual problem, such as torrent tracking or DNS.

It makes me think that there should be a list of viable uses of blockchain, and another list of interesting problems that could be moulded into PoWs, and they should be paired up into blockchains.

Re:A New Largest-Known Prime Number by topmonk on Saturday December 22, 2018 @06:20AM (#18740108)
One problem is that a black hat could solve a lot of primes in secret, and then use those for a double spend attack.

Specifically,

a) Spend some coins to buy some other cryptocurrency

b) use all their secret primes creating a bunch of new blocks on a branch where they haven't spent their money. Since this is the longest branch now, all the other clients accept they haven't really spent it.

c) buy the other cryptocurrency again on this new branch.

Re:A New Largest-Known Prime Number by bouncycastle on Saturday December 22, 2018 @11:42AM (#18741250)
Actually, the problem is that there is no way to control the difficulty. Finding new primes would be harder and harder, but you want the difficulty to adjust up or down to target a block time. Not sure how primecoin approached that problem?

Update: found some clues here, https://www.reddit.com/r/primecoin/comments/1i71ma/strange_b...

Re:A New Largest-Known Prime Number by man-and-laptop on Saturday December 22, 2018 @07:11AM (#18740243)
No. The PoW problem should be derived according to the current state of the blockchain. That makes "solving a lot of primes" in secret inapplicable. You read my post far too literally.

The idea is to combine the ideas behind Namecoin with Primecoin.

Re:A New Largest-Known Prime Number by _trampeltier on Saturday December 22, 2018 @06:10AM (#18740090)
Re:A New Largest-Known Prime Number by bulka on Saturday December 22, 2018 @06:19AM (#18740105)
How would you measure amount of work you want to reward with a coin? In both DNS and torrent examples one can influence a supply of work to be done rather easily
Re:A New Largest-Known Prime Number by man-and-laptop on Saturday December 22, 2018 @07:12AM (#18740247)
It's a broad idea to construct a secure PoW, with all that's required to make it secure, but to try and make it applicable to areas like number theory. See PrimeCoin for a successful example.

Also your concerns are unfounded: See Namecoin and Primecoin. I'm thinking these two ideas could be combined.

[dead]
Re:A New Largest-Known Prime Number by function_seven on Friday December 21, 2018 @09:01PM (#18738407)
Because mathematicians are terrible at supernatural investigation. Not enough rules in the framework.
Re:A New Largest-Known Prime Number by james_s_tayler on Friday December 21, 2018 @11:30PM (#18738919)
Well look at Godels Incompleteness Theorem... Not every statement in mathematics actually even has a proof inside mathematics. So math doesn't even have the tools to fully investigate itself.
Re:A New Largest-Known Prime Number by function_seven on Saturday December 22, 2018 @12:22AM (#18739080)
That's an awesome point. The poor saps have to hand-waive around axioms within their own field. No way they're going to accept divine interventions and invisible dragons in some other line of work :)
Re:A New Largest-Known Prime Number by rohit2412 on Friday December 21, 2018 @09:27PM (#18738531)
Because supernatural is by definition super-natural.

If it was real and explainable by science, we won't call them supernatural

Re:A New Largest-Known Prime Number by krapp on Friday December 21, 2018 @09:03PM (#18738417)
Because prime numbers exist and the soul doesn't.
Re:A New Largest-Known Prime Number by colordrops on Friday December 21, 2018 @11:40PM (#18738947)
You are correct in challenging the GP, but for the wrong reasons. Your statement reveals undue confidence in your assumptions on the nature of objective reality.
Re:A New Largest-Known Prime Number by swampthinker on Friday December 21, 2018 @09:01PM (#18738404)
Perhaps they are related.
Re:A New Largest-Known Prime Number by zahreeley on Friday December 21, 2018 @09:02PM (#18738408)
Hehe
Re:A New Largest-Known Prime Number by spiritcat on Friday December 21, 2018 @09:10PM (#18738459)
you mean like like each prime makes up one of the unique universal souls that exist throughout time and space?

whoa

Re:A New Largest-Known Prime Number by heyjudy on Friday December 21, 2018 @09:25PM (#18738529)
The universe is likely a simulation, so a soul maybe a prime primary key and so use a Mersenne prime to save space as a form of compression because only n needs to be stored, not the full bitstring. The real question is: does the universe have microcode opcodes to operate on Mersenne primes natively without expanding them?

PS: Atheist ;)

Re:A New Largest-Known Prime Number by AnimalMuppet on Friday December 21, 2018 @11:48PM (#18738975)
If the universe is a simulation, isn't the programmer effectively God?

And: "Likely"? Objection, your honor. Assumes facts not in evidence.

Re:A New Largest-Known Prime Number by bouncycastle on Saturday December 22, 2018 @11:21AM (#18741156)
Good call. Well, if humans ever happen to create such a simulator themselves, will they effectively become God?
Re:A New Largest-Known Prime Number by AnimalMuppet on Saturday December 22, 2018 @02:16PM (#18742007)
To the simulation, probably yes.
Re:A New Largest-Known Prime Number by empath75 on Friday December 21, 2018 @10:16PM (#18738704)
This can’t be a serious question but the reason is we know how to find primes.
Re:A New Largest-Known Prime Number by uabstraction on Friday December 21, 2018 @10:52PM (#18738814)
When all you've got is a hammer, everything looks like a nail.
Re:A New Largest-Known Prime Number by social_quotient on Saturday December 22, 2018 @04:22AM (#18739785)
In case anyone wants to know more about the “hammer” expression. I looked it up one day and found it to be interesting

https://en.m.wikipedia.org/wiki/Law_of_the_instrument

Re:A New Largest-Known Prime Number by burtonator on Friday December 21, 2018 @07:22PM (#18737985)
.
Re:A New Largest-Known Prime Number by thestoicattack on Friday December 21, 2018 @07:29PM (#18738012)
Two is prime.
Re:A New Largest-Known Prime Number by zahreeley on Friday December 21, 2018 @09:01PM (#18738399)
According to German science magazine 2 is not prime
Re:A New Largest-Known Prime Number by heyjudy on Friday December 21, 2018 @09:16PM (#18738486)
That's not a primary source and wrong. A prime is most simply: it has no factors other than itself and 1. "Not being even" is a corollary, and would be redundant if included in the definition of primality.
Re:A New Largest-Known Prime Number by schoen on Saturday December 22, 2018 @12:34AM (#18739123)
Another way to see this is to observe that the Fundamental Theorem of Arithmetic would be wrong (or more difficult to state succinctly) if 2 were not considered prime or if 1 were considered prime.

For example, if 2 were not prime, it would be impossible to represent the number 256 (or the number 123456) as a product of primes.

Re:A New Largest-Known Prime Number by srtjstjsj on Sunday December 23, 2018 @01:19PM (#18747477)
Alternatively: "even" means "multiple of 2". Saying "no primes are even" is isomorphic to saying "no primes are multiples of 3 [or any other p you choose]". A claim "n can't be prime if none of the other primes are multiples of n", implies that cannot exist at all.
Re:A New Largest-Known Prime Number by throwawaymath on Saturday December 22, 2018 @02:18AM (#18739427)
This is an excellent rebuttal, nice.
Re:A New Largest-Known Prime Number by lurchedsawyer on Saturday December 22, 2018 @03:41AM (#18739667)
It's not, though. It's one group of mathematicians appropriating prime numbers and jack-booting them into their favourite theorem. There are valid reasons to treat 1 as a prime number, just as there are for defining 0^0 as 1 in some cases. Also for a fun pastime try asking an arithmetician to apply the fundamental theorem to 1 and watch them squirm.
Re:A New Largest-Known Prime Number by schoen on Saturday December 22, 2018 @04:03AM (#18739739)
Presumably the arithmetician will answer that its factorization is the empty set. That's what sympy says, for example.

  >>> sympy.factorint(6)
  {2: 1, 3: 1}
  >>> sympy.factorint(1)
  {}
This definition is also sensible because it also preserves uniqueness in both directions. The empty set is the only prime factorization of 1, and 1 is the only natural number whose prime factorization is the empty set. (Wikipedia has a footnote that "Using the empty product rule one need not exclude the number 1 [from the fundamental theorem of arithmetic], and the theorem can be stated as: every positive integer has unique prime factorization.")

The fundamental theorem doesn't have to state that the prime factorization is nonempty.

It's true that some mathematicians have defined 1 as a prime number and there's nothing logically inconsistent about doing so, but it makes most theorems and formulas in number theory more complex and so this definition has fallen out of favor.

Edit: I think the Wikipedia article on the empty product gives some quite nice examples of the benefits of a closely related concept. https://en.wikipedia.org/wiki/Empty_product

Re:A New Largest-Known Prime Number by impendia on Saturday December 22, 2018 @02:23PM (#18742032)
> Presumably the arithmetician will answer that its factorization is the empty set.

Arithmetician (Ph.D. in number theory) here. This answer is completely correct.

As another reason why the factorization of 1 should be the empty set: suppose you have two positive integers m and n. Write S(m) and S(n) for their sets of prime divisors, counted with multiplicity.

Then S(mn) is the union of S(m) and S(n). We need S(1) to be the empty set to make this rule consistent.

Analogous to how log(1) is equal to 0.

Re:A New Largest-Known Prime Number by Someone on Sunday December 23, 2018 @12:19PM (#18747150)
It also is analogous to the fact that the sum of zero integers equals zero (a claim that, I guess, more laymen will find reasonable)

The analogy is a good one, as zero is the additive identity (https://en.wikipedia.org/wiki/Additive_identity) of the integers, and one is the multiplicative one (https://en.m.wikipedia.org/wiki/1#Mathematics)

Re:A New Largest-Known Prime Number by lurchedsawyer on Saturday December 22, 2018 @06:27AM (#18740127)
See? Squirming. Somehow multiplying 0 factors is supposed to result in 1.

I'm not saying it's incorrect, but you have to explain that edge case away. At the same time allowing 1 to be prime would remove that problem given that e.g. 6 = 2^1 * 3 ^1 and 6 = 1^81 * 2^1 * 3^1 are the same unique factorisation because, well, monoids.

Edit: `s/fields/monoids`

Re:A New Largest-Known Prime Number by srtjstjsj on Sunday December 23, 2018 @01:13PM (#18747436)
How many prime factors does the product of two numbers have? Not the sum of the number of prime factors of the individual numbers.

Now you are the one squirming.

Cleanly accounting for edge cases isn't squirming, it's logical thinking.

Re:A New Largest-Known Prime Number by throwawaymath on Saturday December 22, 2018 @09:10AM (#18740627)
Why would anyone "squirm"? You have an issue with multiplying 0 factors to obtain 1, but you don't have a problem with multiplying a number by itself 0 times to obtain 1?

What the sibling response to my own is correct. It's just the empty set.

Re:A New Largest-Known Prime Number by adtac on Friday December 21, 2018 @09:49PM (#18738623)
>That's not a primary source

Heh.

Re:A New Largest-Known Prime Number by revskill on Friday December 21, 2018 @07:28PM (#18738007)
Number Theory is beautiful, but impractical for daily usage or programming. Who cares ?
Re:A New Largest-Known Prime Number by dang on Friday December 21, 2018 @07:45PM (#18738076)
"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."

https://news.ycombinator.com/newsguidelines.html

Re:A New Largest-Known Prime Number by Cyph0n on Friday December 21, 2018 @08:03PM (#18738168)
That may be true now, but perhaps not in the future.

Heck, mathematicians in general thought number theory was “useless” up until only around 40 years ago. Now we know that our world could not have developed this way without the creation of modern cryptography.

I think number theory serves as a great example for why basic research is so important to humanity.

Re:A New Largest-Known Prime Number by throwawaymath on Saturday December 22, 2018 @02:20AM (#18739432)
Impractical for daily usage? Surely you use TLS daily, in some fashion, do you not?