[seqfan] Re: when is 1234...n a prime?

Frank Adams-Watters franktaw at netscape.net
Sat Oct 3 19:17:33 CEST 2015


I'm interested in what the sequence looks like in other bases. Are there other bases where there are none for a long time? Is the density less than expected across multiple bases?

Note to Elias: I think you are misunderstanding the sequence of numbers to be tested. It's 12345678910111213..., not 123456789123456789....

Franklin T. Adams-Watters

-----Original Message-----
From: Ron Hardin <rhhardin at att.net>
To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
Sent: Sat, Oct 3, 2015 11:49 am
Subject: [seqfan] Re: when is 1234...n a prime?


I'm just curious, without knowing anything about it, if there's a better base
than 10 for such removals.  I mean, why should 10 be the most
efficient? rhhardin at mindspring.com rhhardin at att.net (either)
 
      From: eli
Mcfly <elijaffe173 at gmail.com>
 To: Sequence Fanatics Discussion list
<seqfan at list.seqfan.eu> 
 Sent: Saturday, October 3, 2015 11:50 AM
 Subject:
[seqfan] Re: when is 1234...n a prime?
   
Has anyone taken care to remove
numbers that end in 2,4,5,6,8,and 9 from
the testing algorithm? Some code could
speed up the search.
Numbers that end in 9 are removed because
123456789*100000001000000001...
Will always end in nine.
Elias Jaffe
Just a
brief update -- there are no primes among first 77,000 terms.

Regards,
Max

  


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