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Old 2012-02-12, 09:50   #221
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double post but...i can't resist it...
a japanese show that teach kids how to draw

Last fiddled with by wblipp on 2012-02-15 at 00:17
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Old 2012-02-13, 11:12   #222
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http://www.bbc.co.uk/news/world-asia-china-17009359
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Old 2012-02-16, 06:33   #223
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http://mersenne-aries.sili.net/expon...entdetails=397
http://www.wolframalpha.com/input/?i...42841146073%29

Lol.
@James: Is WolframAlpha correct, in that the cofactor is prime? If so, why is it not listed? I know PrimeNet does it to save space, but...

Nvm the first question, just found your factoring utility.

Last fiddled with by Dubslow on 2012-02-16 at 06:36
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Old 2012-02-16, 08:02   #224
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See also here for factored M397.
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Old 2012-02-16, 12:44   #225
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Quote:
Originally Posted by Dubslow View Post
http://mersenne-aries.sili.net/expon...entdetails=397
http://www.wolframalpha.com/input/?i...42841146073%29

Lol.
@James: Is WolframAlpha correct, in that the cofactor is prime? If so, why is it not listed?
It's been a common practice not to list the largest prime factor in such tables for many decades, starting in the pencil-and-paper days. Those who want to know its value can perform the appropriate divisions to get it.
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Old 2012-02-16, 20:01   #226
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Yes, but they also have to verify whether or not it is prime. These days that is trivial, but in the old days surely they must have marked somehow "Fully factored, last factor not listed."
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Old 2012-02-17, 06:22   #227
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Quote:
Originally Posted by Dubslow View Post
Yes, but they also have to verify whether or not it is prime. These days that is trivial, but in the old days surely they must have marked somehow "Fully factored, last factor not listed."
Did you notice that I wrote, "largest prime factor"?
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Old 2012-02-17, 06:24   #228
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Quote:
Originally Posted by cheesehead View Post
Did you notice that I wrote, "largest prime factor"?
Yes, but the databases don't say that, I have to go check that myself. If no one marks that the exponent is in fact FF, then no one will know that it is prime. It's easy enough to find the cofactor, yes, but nowhere in the databases are the cofactors marked as known primes.

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Old 2012-02-17, 07:38   #229
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Quote:
Originally Posted by Dubslow View Post
Yes, but the databases don't say that
The GIMPS/PrimeNet database doesn't, because GIMPS's goals do not include completely factoring composite Mersenne numbers. It just records all factors that are reported to PrimeNet.

Which other databases have you checked?

Last fiddled with by cheesehead on 2012-02-17 at 07:42
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Old 2012-02-17, 20:12   #230
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mersenne-aries, which you can check was the original DB referenced. It does not report any Mersennes as fully factored. In the example I posted, the last cofactor is prime, but is not listed, and the page shows only "74% factored" or however it is.
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Old 2012-02-22, 18:06   #231
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a new shrooms found in malaysia.. named Spongiforma squarepantsii (national geographic link)
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