/sci/ - Science & Math

3*10 + 3*3

nay

>>8230698
How does 39 not feel prime to you? 3 divides both 10 and 9. Now 1999, that's a number that feels like it should be prime. Conversely 9991 is a number that feels like it should be prime, but isn't.

117

561

51

>>8230719
the bigger a number gets the less likely it is to be prime, so no, 9991 doesn't feel like that

>>8230698
inb4 grothendieck's prime

The Grothendieck prime: 57

>>8230776
I waited for this answer to occur :3

221
1001

>>8230698
60 and 5040

>>8230698
1

>>8230805
Grothendieck was one of the most abstract thinkers in mathematics.

His 1000-page treatise Éléments de Géométrie Algébrique contained only one example.

>>8230805
Grothendieck was one of the most abstract thinkers in mathematics.

His revolutionary treatises EGA and SGA total approximately 10,000 pages, and in all of that contain only a single example.

2

any industrial-grade prime which is composite

>>8230698

This has got to be a troll thread.

>>8230698
1

>>8230827
Bait or retard?

Is pie a prime?
You can certainly eat a slice of it.

It seems like [math]29root(7) - 91 [/math] should be prime in the unique factorization domain [math]\mathbb{Z}[root{7}][/math]

It seems like [math]119+41\sqrt{7} [/math] should be prime in the unique factorization domain [math]\mathbb{Z}[\sqrt{7}][/math].

>>8230827
5041

>>8231111
Why does it seem prime to you?

>>8231111
8231111

>>8231214
It was more like a joke about we (or at least I) have almost no intuition for primality in algebraic extensions.

A number theorist might have some intuition.

284328329121231231879948359839548439853848914387428347283748237847283463344727342727777272993495322042034010300410100400104001000400104003002304020304004

We always have a laugh in math lab about that one, it's so obvious.

I want to factor expressions like [math]119+41\sqrt{7}[/math] over [math]\mathbb{Z}[7][/math] using wolframalpha.

A brief google search revealed that it can do this provided input formatted as such: https://reference.wolfram.com/language/tutorial/PolynomialsOverAlgebraicNumberFields.html

However, when I try this, it just gets confused.

Help?

>>8231294
*Meant [math]\mathbb{Z}[\sqrt{7}][/math], obviously.

>>8231294
The first step is to stop using Wolfram Alpha. You should be able to figure it out from there.

>>8230719
>3 divides both 10 and 9.
>3 divides 10

>>8231294
I'm not sure that feature is what you want to be using for this. You're trying to factor an algebraic integer, not polynomials. This would be akin to trying to get prime factorizations of integers by finding roots of rational polynomials.

>>8230719

>3 divides both 10 and 9

sometimes i don't know whether i hate this board or love this board

>>8230698
[math]\pi[/math]

>>8230698
>feels like a prime
>>8230719
>3 divides both 10 and 9
>>8230827
>60 and 5040

Wow.
>>>/x/ salutes you.
You should stop by and tutor us

15 and 21

>>8230698
GET OUT OF HERE NORMIE!!!!!

>>8230698
111 does sort of feel like it should be prime

>>8231303
Yeah. Start using an actual programming language. Like VBA.

Kappa.

>>8232102
Come on, any number with a digitsum of 3 is divisible by 3.

So 111 does most certainly not feel in any way like it should be prime.

Summerfags.....

https://en.wikipedia.org/wiki/Divisibility_rule

2545841453

>>8230827
>5040
>7 fucking factorial
kek

>>8231343
>>8231695
>>8231740
It was obviously a typo you fucking spergs.

>>8230698
Is no one else curious why someone dedicated a whole website to pictures of numbers?

>>8232376
I think he meant that 3 divides into 30 to make 10

>>8230836
>and in all of that contain only a single example.
Source? Sounds insane

>>8230698
How the fucking fuck does 39 feel like it should be prime when all digits are multiples of 3?
>>8230741
>>8230743
>>8230744
>>8230776
>>8230818
these
>>8232359
yea also 39058320627692063557

My post number should be

>>8230776
what the fuck did i (>>8230770) tell u !?!?!?!?!

91
fuck 91

>>8230744

>>8230827
Even numbers can't be prime. I'm m is any integer then 2m is always even.

53

>>8237575
>Even numbers can't be prime
That's not true.

I bet you think 1 is prime too.

>>8237575
0 and 2 are prime

>>8237586
0 is not prime

>>8237589
Of course it is. If a and b are integers such that ab = 0, then a or b is divisible by 0, just like for all other primes.

>>8230698
this is the shittiest fucking thread I've ever seen

>>8237589
It is prime in the integers, and can in fact fail to be prime in other rings. Whether or not a ring has zero divisors (whether 0 is prime) is actually really important.

>>8230698
>all digits share a common divisor
>doesn't feel prime
I bet you're the type of guy who doesn't find e^(i*pi)=-1 painfully obvious

>>8237598
This. I'm gonna bail out.

Die in a fire all of you

1

>>8231303
>>8232359
>>8237753

check those primes post numbers

>>8237593
>divisible by zero
>>>/x/ salutes you

2 but it's an even number so it can't be one.

>>8237820
>gets triggered by hearing 0 and divisible in the same sentence
You know something's up, but you don't quite know what. And it shows.

>>8237593
>>8237820
i love it when someone who actually knows math sets up a honeypot like this and retards fall right into it.

>>8230705
>feel like it should be
>tries to prove it
>denies
are you fucking retarded my mane ?

In the reverse, I look at 97 and feel like it shouldn't be prime but it is

>>8232424

no he meant 3 divides both 30 and 9 as in

39 = 30 + 9 = 3(10 + 3)

>>8232355
Any integer with more than one digit whose digits are all identical is composite.

>>8239429
Which is the easier way to tell, but of course that's just a special case of finding a number that divides every digit

>>8237300
The thing about prime looking non-primes is that they almost have to be divisible by a two-digit number, because otherwise it's too easy to check for divisors. Secondly, it cannot be too big, or the intuition goes out the window, and it's not convincingly prime enough. Can't have too many prime divisors either, clearly.
Being divisible by 11 is an obvious nono, 17 is too big, so you have to be divisible by 13. The lowest prime-looking non-prime divisible by 13 is 91. This is why, to me, 91 is the ultimate non-prime prime, with 49 being a distant second.

>>8239429
11

>>8231111
Nice quads

>>8239459
And whose absolute value is greater than 11. Fuck

>>8239485
Why (I'm asking about the 111111 ones, obviously).

ITT now: numbers that don't look prime but are

2

>>8239499
Okay, so it's not true for 1. The second repunit prime has 19 digits. But for other digits it's true

>>8239505
The number >>8239558 mentions is pretty surprising

>>8239558
The proof that all repdigits which are not repunits are composite is trivial.

2^5

/thread