bugged sequence in factordb

firejuggler · 2010-06-14, 18:51

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

10metreh · 2010-06-15, 10:39

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.

Andi47 · 2010-06-15, 14:03

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).

2010-06-14, 18:51	#1
firejuggler "Vincent" Apr 2010 Over the rainbow 2×31×47 Posts	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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2010-06-15, 10:39	#2
10metreh Nov 2008 2·3³·43 Posts	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.

2010-06-15, 14:03	#3
Andi47 Oct 2004 Austria 2·17·73 Posts	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).