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Thread: How long will SOB last?

  1. #1

    How long will SOB last?

    It is obviously not infinite... Any guesses how much work there is to do and how long we can expect this project to last?

    Even a worst case scenario estimate would be nice...

    Thanks!

  2. #2
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    Well... there is a chance that we are working on a prime-free sequence (you can read this word k-values, if the other seems nonsense!); in that way, the project won't be ended, unless someone gives an abstract proof, that our sequence is prime free!

    However, if we find a prime, I believe, that there is 2 other sequences, that could have primes as far out as we are now, and even further out!

    So the answer is... we will not know when a prime will be found, but if we find a prime tomorrow, there will be other sequences waiting for us (however, it would be a grand breakthrough to find a prime at this point)! I have heard a rumor, that we will end working on our current sequence, when we reach n= 3,000,000 (or is just that we will also start working on another sequence?); please confirm or reject this rumor.

    One thing I would like to ask, is if anyone actually have read the proof that k=78557 defines a prime-free sequence? And if you have, in what degree, is 78557 "random", and in what degree does it base itselve on the form of 78557. I would like to get a touch of the possibility of this conjecture being true!

    What magazine, year and number is the proof in?

  3. #3
    A good starting point for sierpinski numbers is http://www.prothsearch.net/sierp.html. There are a few links on that site which you should follow.

    It will take quiet a while to find a factor for all of the remaining sequences. See http://groups.yahoo.com/group/primenumbers/message/878 for some numbers.

    But that is to solve all the remaining numbers (19 in the link above, 17 currentely). Chances that one of the remaining numbers has a prime within our range is of course much higher.

    The last i heard is that the current K will indeed be searched up to 3 million (about 1500 numbers left currentely). After that we will start testink k=33661 which is currentely only at 645600.
    But i guess with this distributed project we will reach 3 million for that next K pretty fast.

  4. #4
    Sieve it, baby!
    Join Date
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    Well, it took mankind 41 years to get down to 17 remaining could-be-Sierpinskis. So I guess it's quite fair to continue that work and sieve out as much numbers as we can, so that there will be a final result somewhere in the (hopefully not so far) future.
    As the likeliness of a prime (maybe only relative to the needed effort, but that's what counts here) decreases with the increase of n (at least as far as I unterstood) it should be a wise idea to keep the remaining number tests at a more or less even level.

    btw. the prothsearch site states that n(max)tested is 1952000 as of November 5th. Is there a season why? I mean, it's the 7th now and inclusively it's 1929452, the highest of 'em all is much higher...

  5. #5
    Sieve it, baby!
    Join Date
    Nov 2002
    Location
    Potsdam, Germany
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    Hey, how many n's are still missing to 2M? And where's the big jubilee party?

    Sorry for this "double post" - seems like editing is only possible within 60 seconds...

  6. #6
    there is a warning on the page by the bound right now:

    "some testing is occuring, below bound may be low"


    I will someday make a stat script (or graph) that shows how many values are below each value. Right now it's like this:

    2 : < 200000
    2 : 2000000 - 2100000
    18 : 2100000 - 2200000
    32 : 2200000 - 2300000


    -Louie

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