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Forum: Puzzles 2010-12-28, 02:44
Replies: 183
Views: 14,450
Posted By CRGreathouse
Cool See post #165.

See post #165.
Forum: Puzzles 2010-12-28, 02:42
Replies: 183
Views: 14,450
Posted By CRGreathouse
Is that blind faith, or do you have some reason...

Is that blind faith, or do you have some reason for this belief?
Forum: Puzzles 2010-12-28, 02:26
Replies: 183
Views: 14,450
Posted By CRGreathouse
Hardy-Littlewood conjectures -- there were quite...

Hardy-Littlewood conjectures -- there were quite a few.



Good question; I don't know the answer.
Forum: Puzzles 2010-12-28, 02:00
Replies: 183
Views: 14,450
Posted By CRGreathouse
http://lmgtfy.com/?q=k-tuple+conjecture

http://lmgtfy.com/?q=k-tuple+conjecture
Forum: Puzzles 2010-12-28, 01:53
Replies: 183
Views: 14,450
Posted By CRGreathouse
"My" k-tuple conjecture? I'm neither Hardy nor...

"My" k-tuple conjecture? I'm neither Hardy nor Littlewood.

I quite doubt that proving your sequence infinite would help prove the k-tuple conjecture.
Forum: Puzzles 2010-12-28, 01:37
Replies: 183
Views: 14,450
Posted By CRGreathouse
Was it to turn up hidden treasures, it would be...

Was it to turn up hidden treasures, it would be named at that point.
Forum: Puzzles 2010-12-28, 01:35
Replies: 183
Views: 14,450
Posted By CRGreathouse
I'm skeptical. The proof I had in mind wouldn't...

I'm skeptical. The proof I had in mind wouldn't generalize to anything like Mersenne numbers. It would just set up lots of numbers such that (because of congruence conditions) omitted interior...
Forum: Puzzles 2010-12-15, 04:40
Replies: 183
Views: 14,450
Posted By CRGreathouse
Depending on what you mean by "easy" and on how...

Depending on what you mean by "easy" and on how far apart the primes are, there might be.
Forum: Puzzles 2010-12-15, 04:36
Replies: 183
Views: 14,450
Posted By CRGreathouse
On the other hand, you don't know what happens...

On the other hand, you don't know what happens when you run isprime() or factor(). In fact most functions have this kind of hidden stuff going on and don't expose it.

Speaking of which I was just...
Forum: Puzzles 2010-12-14, 20:11
Replies: 183
Views: 14,450
Posted By CRGreathouse
Likewise -- I wanted one enough that I sat down...

Likewise -- I wanted one enough that I sat down and wrote one. But there are still fencepost errors, and also a few things I'd like to optimize before I send it out.

The version I have right now...
Forum: Puzzles 2010-12-14, 19:54
Replies: 183
Views: 14,450
Posted By CRGreathouse
Right. The mingw project that the Windows...

Right. The mingw project that the Windows version of Pari/GP is built on is strictly 32-bit. There is a mingw64 fork, but the last time I used it there were serious problems with it. I've heard...
Forum: Puzzles 2010-12-14, 17:36
Replies: 183
Views: 14,450
Posted By CRGreathouse
Glad to hear it. I think I checked to...

Glad to hear it.



I think I checked to 10^10 without finding any further terms. 64-bit Pari doesn't have the 4294965247 limitation. :smile:

I really need to stop being lazy and finish my...
Forum: Puzzles 2010-12-14, 17:25
Replies: 183
Views: 14,450
Posted By CRGreathouse
I was trying to make my code act the same as...

I was trying to make my code act the same as yours. If (say) you just wanted one answer for each size, do
find(m)={
my(s=Mod(0,m));
forprime(p=2,default(primelimit),
s+=Mod(p,m)^p;
...
Forum: Puzzles 2010-12-14, 16:03
Replies: 183
Views: 14,450
Posted By CRGreathouse
huh? I was talking about your code in #126: ...

huh? I was talking about your code in #126:
a=0;for(m=1,2,for(n=1,1000,a=a+prime(n)^prime(n);if(a%(10^m)==0,print(n":"m)));a=0)

which can be improved like so:...
Forum: Puzzles 2010-12-14, 15:39
Replies: 183
Views: 14,450
Posted By CRGreathouse
The basic idea: Pari stores the differences...

The basic idea: Pari stores the differences between primes up to primelimit, so it can quickly go from one prime to the next in as long as it knows where it is on the list. (It's can't use that for...
Forum: Puzzles 2010-12-14, 04:37
Replies: 183
Views: 14,450
Posted By CRGreathouse
Well, that's what I get for trying to help...

Well, that's what I get for trying to help improve your programming skills. :smile:



It's pretty much faster in all cases. prime() is very inefficient, it typically just goes through the...
Forum: Puzzles 2010-12-13, 23:57
Replies: 183
Views: 14,450
Posted By CRGreathouse
As a rule of thumb, any time you write ...

As a rule of thumb, any time you write

for(n=1, _, ... prime(n) ...)

you should be writing

forprime(p=2, prime(_), ... p ...)

instead.
Forum: Puzzles 2010-12-13, 04:45
Replies: 183
Views: 14,450
Posted By CRGreathouse
It's heuristically infinite with the n-th term...

It's heuristically infinite with the n-th term about 2.3n * 10^n. I doubt it can be proven infinite with present technology, but a conditional proof on the k-tuple conjecture seems plausible (though...
Forum: Puzzles 2010-12-13, 03:43
Replies: 183
Views: 14,450
Posted By CRGreathouse
Nothing to 10^10.

Nothing to 10^10.
Forum: Puzzles 2010-12-13, 02:54
Replies: 183
Views: 14,450
Posted By CRGreathouse
Five, actually -- it will be fourth and fifth on...

Five, actually -- it will be fourth and fifth on your list:

11, 751, 1129, 361649, 361649, 12462809, 12462809, 1273183931, 1273183931.

Would someone check me on these? The repeating entries...
Forum: Puzzles 2010-12-12, 21:43
Replies: 183
Views: 14,450
Posted By CRGreathouse
Nah, it turns out it's only 361,649. My code had...

Nah, it turns out it's only 361,649. My code had been storing the full numbers (which are large) and was running slowly as a result.
Forum: Puzzles 2010-12-12, 21:19
Replies: 183
Views: 14,450
Posted By CRGreathouse
11, 751, 1129, then something big. Why?

11, 751, 1129, then something big.



Why?
Forum: Puzzles 2010-04-22, 03:46
Replies: 183
Views: 14,450
Posted By CRGreathouse
I'm looking at your posts on the other forum. ...

I'm looking at your posts on the other forum. You write:
#include <math.h>
#include <stdio.h>
#include <limits.h>
#pragma precision=log10l(ULLONG_MAX)/2

typedef enum { FALSE=0, TRUE=1 } BOOL;...
Forum: Puzzles 2010-04-22, 03:12
Replies: 183
Views: 14,450
Posted By CRGreathouse
Your code only works below 2319529. It uses...

Your code only works below 2319529. It uses 32-bit signed integers, so even if you added the next 4623 primes you could only use it for numbers up to 2147483647.

To check the primes up to 18...
Forum: Puzzles 2010-04-22, 02:56
Replies: 183
Views: 14,450
Posted By CRGreathouse
It's part of Pari, not part of gp2c. gp2c just...

It's part of Pari, not part of gp2c. gp2c just creates source code like what I posted.



C doesn't support large numbers, so you either need to write routines to work with large numbers or use...
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