/sci/ - Science & Math

>>8019732
1

>>8019763
2

>>8019774
3

>>8019763
5

7

11

(2^74,207,381)-1

>>8019732
>where are all the prime numbers
In the set of all positive integers. It is that easy, if you aren't a stupid fuck.

13

>>8019732
>where are all the prime numbers

[math]P \subset \mathbb{N}[/math]

>>8019763
[math]1[/math] is NOT prime.

17

19

23

29

31

[Last 2 digits of my post number]

57

>>8020441
holy shit

>>8020441
check my primes

>>8020451
Prime roll thread

>>8020529
>>8020441

>>8019732
>2
>>8019763
>3, 19763
>>8019873
>3, 73
>>8019911
>11, 911, 8019911
>>8019935
>5
>>8020023
>23, 20023
>>8020373
>3, 73, 373
>>8020387
>7, 8020387
>>8020441
>41, 20441
>>8020465
>5
>>8020529
>29
>>8020547
>7, 47, 547

Rolling for that Grothendieck

Rolling for 2 prime: best prime

>>8020651
2 isnt a prime number, dingus

Rollin

check it

>>8020657
Lrn2prime fgt pls

Check em

>>8020450
underrated

I guarrantee my post is going to be composed of prime numbers

>>8020657
Kek. Then it's divisible by 1, itself, and what else exacly?

>>8019732
Rolling

check my postnumber faggot

>>8021131
2 is even so it cant be prime

>>8019935
Zero is a prime.

>>8021411
Then why is (2) a prime ideal?

78
I have a 50% chance I get this right, either I get it or I don't

2 is prime number

Check em

check my prime pls

>>8021716
Prove it

CHECKEM

>>8020564
holy shit.

>>8019763
1 is not prime

>>8019935
Then why do they hand out huge cash prizes to anyone who finds a new one?

>>8022011
>>8019935
Misread never mind

>>8020450
grothendieck pls leave

CHECK 'EM

Please let prime rolling spread to other boards

>>8020441
Checked.

>>8022194
Let's make a thread in
>>>/b/

>>8021411
>every prime must be odd

You pulled that "definition of a prime" outta your ass when exaclty?

The actual definition is pretty much what >>8021131 said (i.e. if a number is divided only by 1 and itself, it's prime). 2 happens to satisfy that condition, thus it is prime (no other even number can be prime though for obvious reasons).

>>8022803
But [math]2|2\Rightarrow 2\in 2\mathbb{N}\not\subset \lvert \operatorname{Spec}(\mathbb{Z})\rvert [/math]

last 3 digits = prime

>>8022803

why would you even reply to that..

>>8023101
>>8023038
>>8022803
>>8022593
>>8022049
>>8022013
>>8022011
>>8021943
>>8021937
>>8021917
>>8021729
>>8021721
>>8021411
>>8021389
>>8021131
>>8020753
>>8020663
>>8020657
>>8020651
>>8020629
>>8020547
>>8020529
>>8020451
>>8020441
>>8020387
>>8020373
>>8020023
>>8020009
>>8019911
>>8019873
>>8019763

got a couple of primes here

>>8023038
If 2 is not prime, then what are the prime factors of 2?

Checkmate, atheist.

>Wut is da biggest number?
If only it were this easy.

there literally exists a polynomial whose range is the primes.

>>8023123
I had no idea prime numbers were so common between 8,019,763 and 8,023,101

>>8023228
Roughly every 15 numbers in that range is prime.

>>8019732
>eyo cracka where da prime numbas at

123419081459012735129037589730458170925891024590218357901248597012459910245709120954781098245901254098719081245798019280457901295047819802578901245798012359809102453897012390587128903509821359801235908123905812398051928035980123590123419081459012735129037589730458170925891024590218357901248597012459910245709120954781098245901254098719081245798019280457901295047819802578901245798012359809102453897012390587128903509821359801235908123905812398051928035980123590781980257890124579801235980910245389701239058712890350982135980123590812390581239805192803598012


Prove me wrong. Protip faggots: you can't

>>8023343
Not prime, divisible by 2

>>8023354
>divisible by 2

Prove it faggot

>>8023343
Not prime, divisible by 123419081459012735129037589730458170925891024590218357901248597012459910245709120954781098245901254098719081245798019280457901295047819802578901245798012359809102453897012390587128903509821359801235908123905812398051928035980123590123419081459012735129037589730458170925891024590218357901248597012459910245709120954781098245901254098719081245798019280457901295047819802578901245798012359809102453897012390587128903509821359801235908123905812398051928035980123590781980257890124579801235980910245389701239058712890350982135980123590812390581239805192803598012

>>8023343
how can you fuck up this badly...

>>8023361
it ends with a 2:
>....192803598012

>>8023432
So? 1093210409812342 ends in 2 as well, and that doesn't mean it's divisible by 2. You can't just look at a number and tell if it's divisible by 2 you moron

>>8023437
Stop
This isn't even funny shitposting

>>8023437

you're trolling a bit too hard now

>>8023437
Let me guess: you're an engineer

>>8023437
come on, you can't even pretend to be this stupid.

>>8023452
So what if I am? How does that have anything to with thsi?

>>8023500
Dude you know how 4chan views "pretending to be retarded"

>>8023445
>>8023446
>>8023500
Factoring is a hard problem you dipshits. If you could just look at a number and tell what it's divisors are from the last digit, factoring would be easy. Plus, counterexample:

23 ends with a 3, but it is not divisible by 3

>>8023507
>Factoring is a hard problem you dipshits
Not if it ends in a 2

>>8023511
Okay factor that number I gave you then if it's so easy

>>8023515
stop this charade

>>8023520
>I realized he's right, better accuse him of trolling

/sci/ sucks since the high schoolers came tbqh

Okay guys a I googled it and it turns out it's kind of right, but ONLY for 2. So you all still look like a bunch of morons for claiming you can look at the last digit to tell if it's divisible by something

>>8023522
No, it's just that you misread their original point, then I missed that first time round.

They were saying that being able to tell whether a number is divisible by 2 is not an issue. You then somehow misinterpreted that as them saying that factorising any number is easy, because you're a complete retard

>>8023530
Fuck off, like you never make mistakes. And so what that I never learned that fact about 2? It's a piece of meaningless trivia probably regurgitated by popsci idiots

>>8023532
Actually, you can instantly know that any number that ends in 2, 4, 6, 8, or 0 is not prime because they will be divisible by 2. All even numbers are divisible by 2, and therefor can not be prime

this is the most basic of basics to finding a prime number

>>8023515
123419081459012735129037589730458170925891024590218357901248597012459910245709120954781098245901254098719081245798019280457901295047819802578901245798012359809102453897012390587128903509821359801235908123905812398051928035980123590123419081459012735129037589730458170925891024590218357901248597012459910245709120954781098245901254098719081245798019280457901295047819802578901245798012359809102453897012390587128903509821359801235908123905812398051928035980123590781980257890124579801235980910245389701239058712890350982135980123590812390581239805192803598012
divided by 2 equals exactly
61709540729506367564518794865229085462945512295109178950624298506229955122854560477390549122950627049359540622899009640228950647523909901289450622899006179904551226948506195293564451754910679900617954061952906199025964017990061795061709540729506367564518794865229085462945512295109178950624298506229955122854560477390549122950627049359540622899009640228950647523909901289450622899006179904551226948506195293564451754910679900617954061952906199025964017990061795390990128945062289900617990455122694850619529356445175491067990061795406195290619902596401799006

did it in my head btw

>>8023537
Ohhhhh because 10 is also divisible by 2 so you only need to look at the last digit. So it works with 5 too. Neat. Sorry I was rude anon

>>8023532
>so what that I never learned that fact about 2? It's a piece of meaningless trivia probably regurgitated
I'm going to stop you right there and point out that divisibility by 2/the concept of even number is literally a grade school concept. Either you're trolling, literally autistic, or you just plain don't belong on /sci/ at all. I haven't read the thread.

>>8023541
Please tell me this isn't serious.

>>8023538
you did it in ur ass
fgt

>>8023526
you can also add up all the digits and if the sum of digits is divisible by 3, the number is divisible by 3. that only works in base 10, but that's okay because every base is base 10

>>8023532
Well you were right about the fact that I'm in High School, so at least you've got that going for you

>>8023566
I've met people that would employ this exact type of trolling. It's easily not serious.

All even numbers are divisible by 2 you fucking faggot. That's the definition of an even number.

>>8019732
in this post number

>>8019732
>if only it was this easy

Nobody said it would be, should be, or even could be.

Rolling for a prime

I don't want a prime

>>8023570
The pic is so fucking clever... I never thought that.

>>8023452
>shits on engineers
>lives in a house, drives a car, drives on roads and streets, use a cellphone, use a AC, use a heater,....
Cool, brah

>>8023935
That is literally what defines base numbers. How can you know about base numbers but not know that?

>>8019732
Rolling

4

>>8023935
>>8024032
"Every base is base 10" means as much as "I am always myself". Every base is "base 10" when expressed in itself, just as I am always "myself" when I refer to myself.

>>8024032
>someone learns something
>"fucking brainlet how did you not already know this?"

>>8021716
Doesn't a prime have to be a posotive integer greater than 1?

>>8023541
No prime numbers can end in 0,2,4,5,6,8 with the exception of the actual number 5

>>8025095
What about the actual number 2?

>>8025084

Yes. Yes it does. see wiki for more.

Among 0,1,2,3,4,5 and 6, for example,

we say that 2,3 and 5 are prime, (and further that 2 /is the smallest prime number, and even further the only even prime/)

we say that 4 and 6 are composite (and further that 4 /is the smallest composite number/)

And we say the following of both 0 and 1:

"It is NEITHER prime, NOR composite."

This is settled mathematical terminology. the adjectives "prime" and "composite" are reserved for natural numbers strictly greater than one, and they partition that set (natural numbers greater than one) into two disjoint subsets. Nothing else counts as either one of those, not rational numbers, not zero, not complex numbers with imaginary parts, not your mother's maiden name...*

*(that said, I do own a recent abstract algebra text which defines primes, for its treatment, according to the above definition, /but adds their negatives into the mix: -2,-3,-5,-7.../. This is unusual and, if memory serves, a mostly-cosmetic choice on the author's part to make such-and-such theorems work according to his program without doing book-keeping differently. It is still true that what I wrote above is the standard these days.)

>>8023123
Hello Michael

>>8020441
Ayy, but check mine.

>>8025156

Of course, if a given rational number turns out to be equal to a natural number greater than one, then that is a trivial exception to what I wrote. :^) And so there's no need to point it out.

in the set of natural numbers ?

>Can integer factorization be done in polynomial time?

For int i = 0 to (number / 2)
if (number % i == 0)
add i to list Factors

int n = length of list Factors
For int i = n to 0
add (number / Factors) to list Factors


there is literally nothing special about prime numbers whatsoever

>>8025199
> if (number % i == 0)
And what's the complexity class of this function?

>>8025199

that gets all divisors, not the prime factors

this is a prime thread friend

>>8025199
You still have to do prime factorization of all of those factors you found. Horrible algorithm.

>>8025199
>
>

Your tags have no power here, /g/andalf the /g/rey.

>>	Anonymous Sat Apr 23 19:49:09 2016 No.8026159 File: 117 KB, 336x290, Check_Em.png [View same] [iqdb] [saucenao] [google] >>8025204 check my primes

>>	Anonymous Sat Apr 23 19:57:03 2016 No.8026171 >>8025204 >implying Primes aren't holding our online security right now

>>	Anonymous Sat Apr 23 19:59:27 2016 No.8026175 >>8026171 >mfw I'm prime

>>

Anonymous Sat Apr 23 20:00:12 2016 No.8026177 >>8026171 Good point. What would information security be based on if the primes didn't exist (I know they must exist, but just for the sake of argument let's pretend for a moment they somehow don't)? What would be the next-best thing to base cryptography algorithms on?

>>	Anonymous Sat Apr 23 20:01:21 2016 No.8026181 >>8026177 There's already something better my man, and that is elliptic curves.

>>

Anonymous Sun Apr 24 16:15:51 2016 No.8027691 >>8023123 >needing almost 6seconds to check a couple of numbers if they are prime or not Dude just use the number to create an RSA key and encrypt and decrypt some sample text with the RSA key. If the decrypted text is equal to the sample text you got a prime number. I believe there are much faster methods to check if a number is a prime, but I don't know.

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