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Old 2010-06-14, 18:51   #1
firejuggler
 
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Apr 2010
Over the rainbow

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Default bugged sequence in factordb

while browsing aliquot sequence, I stumbled upon these
Code:
Start    Length  End    Ends  with 
794280 830       Prime P107
794196 438       Prime P106
789090 597       Prime P101
789740 608       Prime P100
790248 1278     Prime P91 
792756 703       Prime P90
790884 1193      Prime P89 
794880 560       Prime P85 
792864 887       Prime P85 
792820 835       Prime P85 
791196 1853     Prime P83 
789816 1030     Prime P82 
765552 103      Prime P27
all these end in a 'even' prime... wich is just wrong. I tried to repair the sequence many time without success

Last fiddled with by firejuggler on 2010-06-14 at 18:54
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Old 2010-06-15, 10:39   #2
10metreh
 
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Nov 2008

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This bug is known. There used to be a "Set prime" button which was given to certain (trusted) users of the DB. It was meant to be used on very large numbers that had been proved prime. However, it obviously got given to someone with malicious intents by mistake, and that person used it to set various composite numbers prime. The "Set prime" button was removed.
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Old 2010-06-15, 14:03   #3
Andi47
 
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I thought the false primes have been fixed when the "set prime" button was removed. (AFIK Syd has (or intended to?) set all primes to "unknown" followed by a primality check.)

I have emailed Syd about the (new?) false primes yesterday in the late evening (Central European Summer Time).
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