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 2003-12-22, 14:30 #1 Ice9   1D1B16 Posts Who has a list? While not completly mersenne related, I was wondering who keeps a list of all known primes. I understand that the list would be way too big to easily distribute, but are there people or organizations that are recognized to have the entire list? I coudn't even find a reference to who might have such a list. Also, does anyone here know of any lists avaliable in the 90 to 100 digit range? Thanks
 2003-12-22, 17:47 #2 only_human     "Gang aft agley" Sep 2002 375410 Posts In my opinion the best place to look is Prime Pages maintained by Dr Chris Caldwell. The is an extremely good site that is very rewarding to read on many levels. As far as prime lists go this is the page on that site: Lists of Primes at the Prime Pages In this information is a list of the 5000 largest known primes, a list of small primes and others. In the small prime list are some 110 to 200 digit primes (and many others too) I defer to others here concerning questions about entire complete lists of primes. Last fiddled with by only_human on 2003-12-22 at 17:54
 2003-12-22, 20:41 #3 ewmayer ∂2ω=0     Sep 2002 República de California 5·2,351 Posts Any list of the actual primes below some bound B grows exponentially fast with the number of digits in B (i.e. with log B, where the log is to any base), so such lists are not generally kept, as it is faster to simply generate said primes when needed and only explicitly store the ones that are needed at the moment. We know that the number of primes < B scales as B/ln B (natural log here), so e.g. below 2^32 (rouhgly 10^10) we have nearly 2^28 primes, each of which would need ~4 bytes to store explicitly, for a total of roughly a Gigabyte. There are ~10^98 primes < 10^100, which is vastly more than the number of elemntary particles in the known universe. What people have done along these lines is to actually count the number of primes below some ever-increasing bound, to check the accuracy of various asymptotic formulae which approximate the prime-count function. At present, the prime count has been exactly enumerated to slightly above 10^20, so 10^100 is a long way off! Remember, actual enumeration requires on the order of as many CPU-cycles as primes, and in all of human history there have been just slightly above a mole (6.23...X 10^23) of CPU-cycles. Even were this count to double each year, it would take over 300 years to reach 10^100. Here are some related links from MathWorld: http://mathworld.wolfram.com/PrimeNumberTheorem.html http://mathworld.wolfram.com/PrimeCountingFunction.html
2003-12-23, 00:51   #4
Reboot It

Aug 2002
London, UK

3·31 Posts

Quote:
 Originally posted by ewmayer ... and in all of human history there have been just slightly above a mole (6.23...X 10^23) of CPU-cycles.
I know this doesn't alter the argument, but, just for the record, Avogadro's constant is actually reckoned to be 6.02214199 x 1023. See for example the National Physical Laboratory website's useful PDF reference guide to fundamental physical constants and conversion factors.

I only point this out because if I don't, somebody else will (honest!).

2003-12-23, 15:40   #5
ewmayer
2ω=0

Sep 2002
República de California

5×2,351 Posts

Quote:
 Originally posted by Reboot It I know this doesn't alter the argument, but, just for the record, Avogadro's constant is actually reckoned to be 6.02214199 x 1023.
Thanks - can you tell I'm a long ways removed from my college chemistry courses?

I know this doesn't alter the argument, but, just for the record, it's really the Loschmidt constant, as Avogadro never made any estimate of the number itself.

Last fiddled with by ewmayer on 2003-12-23 at 15:41

 2003-12-23, 19:44 #6 Reboot It     Aug 2002 London, UK 5D16 Posts Touché!
2003-12-29, 19:35   #7
frodsham

Dec 2003
Frodsham, uk

1002 Posts

Quote:
 Originally posted by ewmayer I know this doesn't alter the argument, but, just for the record, it's really the Loschmidt constant, as Avogadro never made any estimate of the number itself.
Not really, because if you read

Quote:
 Originally posted by Reboot It See for example the National Physical Laboratory website's useful PDF reference guide to fundamental physical constants and conversion factors.
you'll find
Quote:
 Loschmidt constant (Na/Vm) ~= 2.686 7775 x 10^25 m^-3
The "mistake" was to call it Avogadro's constant rather than [the] Avogadro constant.

Mathematical pedantry can be such fun.

2003-12-29, 19:53   #8
frodsham

Dec 2003
Frodsham, uk

22 Posts

Quote:
 Originally posted by frodsham Mathematical pedantry can be such fun.
And, moreover, Avogadro was 21.5 times better than Loschmidt. When I was young that was the density of Platinum, though it isn't now.

(The ratio of relative uncertainties in the 2 constants.)

2003-12-30, 15:28   #9
ewmayer
2ω=0

Sep 2002
República de California

2DEB16 Posts

Quote:
 Originally posted by frodsham Mathematical pedantry can be such fun.
Would this discussion best be characterized as mathematical or nomenclatural pedantry? Is it pedantic of me to ask that?

2004-01-27, 16:32   #10
mfgoode
Bronze Medalist

Jan 2004
Mumbai,India

205210 Posts
Who has a list?

Quote:
 Originally Posted by Ice9 While not completly mersenne related, I was wondering who keeps a list of all known primes. I understand that the list would be way too big to easily distribute, but are there people or organizations that are recognized to have the entire list? I coudn't even find a reference to who might have such a list. Also, does anyone here know of any lists avaliable in the 90 to 100 digit range? Thanks
Try this website out and click on HOW MANY.

http://www.utm.edu/research/primes/mersenne/index.html

Mally

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