What's the biggest prime you can find on your TI-89/TI-92?

[Dissipate]

I was tooling around with my TI-89's factor function. Surprisingly I found some pretty large primes that were factors of some big numbers. What's the biggest one you can find with your TI-89/92?

So far biggest I found:

24413334027024214953767

 

[DAGTA]

Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

 

[Crusty]

I have a java program that finds Marsenne Primes... i'm not sure what # it can go up to... but I think it's in the 30's somewhere...

Keep in mind, we are talking in the several hundred thousand digits...

http://primes.utm.edu/largest.html#Mersenne

 

[Dissipate]

Originally posted by: DAGTA
Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

That's cool. :thumbsup:

Sounds like that thing would be useful for generating encryption keys.

 

[AccruedExpenditure]

is 101 prime? yes
is 1001 prime? yes
is 10001 prime? yes
is 100001 prime? yes

Continue to your hearts content.

 

[Crusty]

Originally posted by: Dissipate

Originally posted by: DAGTA
Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

That's cool. :thumbsup:

Sounds like that thing would be useful for generating encryption keys.

I had to write an RSA encryption function, that would have to "randomly" generate x-bit prime numbers.... let's just say that it took a while to generate a 4096-bit prime number randomly!

 

[Dissipate]

Originally posted by: AccruedExpenditure
is 101 prime? yes
is 1001 prime? yes
is 10001 prime? yes
is 100001 prime? yes

Continue to your hearts content.

HuH? What are you smoking? 1001 is not prime. Its factors are:

7 * 11 * 13

In fact, the only one that is prime on your list is 101. Nice try.

As far as anyone knows, the distribution of the primes is random. You never know when one will pop up.

 

[DAGTA]

Originally posted by: Dissipate

Originally posted by: DAGTA
Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

That's cool. :thumbsup:

Sounds like that thing would be useful for generating encryption keys.

That's exactly what it was used for. I was taking an Encyption class in Spring 2001 and we were working with RSA level encyption. Some of the coolest stuff I've ever coded. Some of the hardest mathematics I've ever dealt with.

 

[Dissipate]

Originally posted by: DAGTA

Originally posted by: Dissipate

Originally posted by: DAGTA
Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

That's cool. :thumbsup:

Sounds like that thing would be useful for generating encryption keys.

That's exactly what it was used for. I was taking an Encyption class in Spring 2001 and we were working with RSA level encyption. Some of the coolest stuff I've ever coded. Some of the hardest mathematics I've ever dealt with.

Yeah. That number theory stuff is craaaaaazy abstract. Crytography is for super-geeks, imo. I'm a math-CS major myself, but fortunately I don't have to take number theory. Right now I'm in abstract algebra, and that is bad enough.

 

[Crusty]

Originally posted by: DAGTA

Originally posted by: Dissipate

Originally posted by: DAGTA
Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

That's cool. :thumbsup:

Sounds like that thing would be useful for generating encryption keys.

That's exactly what it was used for. I was taking an Encyption class in Spring 2001 and we were working with RSA level encyption. Some of the coolest stuff I've ever coded. Some of the hardest mathematics I've ever dealt with.

Meh, RSA is easy I find Rabin's Information Dispersal Algorithm a bit more difficult then RSA.

 

[DAGTA]

Originally posted by: Dissipate

Originally posted by: DAGTA

Originally posted by: Dissipate

Originally posted by: DAGTA
Ok, it's not on a TI, but I wrote a program back in grad school that will generate prime numbers non-deterministically for any length you specify. I ran it on the CS dept's mainframe a few times. The largest I went was a 997 digit prime number. I think that took 4 hours.

That's cool. :thumbsup:

Sounds like that thing would be useful for generating encryption keys.

That's exactly what it was used for. I was taking an Encyption class in Spring 2001 and we were working with RSA level encyption. Some of the coolest stuff I've ever coded. Some of the hardest mathematics I've ever dealt with.

Yeah. That number theory stuff is craaaaaazy abstract. Crytography is for super-geeks, imo. I'm a math-CS major myself, but fortunately I don't have to take number theory. Right now I'm in abstract algebra, and that is bad enough.

I remember it took me almost two weeks to get the math of 4 pages of a graduate level mathematics text converted into programming code without bugs. Jacobi's alogorith and Legendre's algorithm. Non-deterministic mathematics are really interesting though. Nothing else is quite like telling your program that you want to get a number that has a 98% probablity of being prime and knowing that the higher you up that probability, the longer it will take to run.

 

[Dissipate]

Here is one I was thinking of how to program: an algorithm for finding phi(n), such that phi is the Euler phi function. Euler phi function is the number of numbers relatively prime to n, and less than n.

 

[PurdueRy]

Originally posted by: AccruedExpenditure
is 101 prime? yes
is 1001 prime? yes and I am retarded
is 10001 prime? yes and I am retardeder
is 100001 prime? yes and I am the retardest

Continue to your hearts content.

FIXED

 

[remexido89]

sorry, y think that number is not a prime number:

-24413334027024214953767

-13487100017777(this is more small, bu it's prime).

 

[Red Squirrel]

I suck at math, what's the formula to find a prime? I will write a program and see what I can get.

I imagine on a computer using standard integer formats you would be limited by whatever n^64 comes up to though, without coding a library that can "artificially" do the math and use strings.

 

[silverpig]

I suck at math, what's the formula to find a prime? I will write a program and see what I can get.

I imagine on a computer using standard integer formats you would be limited by whatever n^64 comes up to though, without coding a library that can "artificially" do the math and use strings.

I'm sure there are more efficient ways to do this, but basically you just check to see if the number n is divisible (ie mod 0) by any prime less than n/2, and you probably want to start at the bottom (so divide by 2, then 3, then 5, 7, 11...)

 

[edro]

U-u-u-u-ltra, Necro!

 

[T_Yamamoto]

Wow what's the story here??? Why have I been paying 30+ dollars for a color cartridge???

It's been ages since I've been around AnandTech. It's good to see that the Hot Deals is still A1.

I'll be ordering from this place.

Agreed

 

[TridenT]

Agreed

Yeah... wrong thread.



Who else realized this was a necro once they noticed the nested quotes? I don't usually view thread dates immediately. (Should, but I forget to)

 

[Red Squirrel]

I'm sure there are more efficient ways to do this, but basically you just check to see if the number n is divisible (ie mod 0) by any prime less than n/2, and you probably want to start at the bottom (so divide by 2, then 3, then 5, 7, 11...)

Ahh I see so like 3, 5, 7, 13 etc...

 

[Jeff7]

What's the oldest thread you can find with your TI-89/TI-92?

 

[remexido89]

try this:

http://www.csgnetwork.com/mthprimenumber.html

 

[portuga]

sorry, y think that number is not a prime number:

-24413334027024214953767

-13487100017777(this is more small, bu it's prime).

------------------------------------------

the program is a funcion for the TI-89, wering the funcion "isprime()" that returns "true" or "false". If you put the calculator in the mode "exact" you can get prime nunbers as big as 360 digits.

the funcion returns the next prime number, given a prime number:

[define nextPrime(n)=func:loop:n+1:if isprime(n):return n:endloop:endfunc], then, enter, it says "done".

after put in hom nextprim(7), for intance, an retuns 11, an so one, but in the exact mode.


i get this one:

244133402702400000000000000000000000000000000000000000000053
(45 consecutive zeros), in a total 60 digits.

 

[Chaotic42]

I suck at math, what's the formula to find a prime? I will write a program and see what I can get.

I imagine on a computer using standard integer formats you would be limited by whatever n^64 comes up to though, without coding a library that can "artificially" do the math and use strings.

GNU MP Bignum Library

 

[MongGrel]