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

Max Alekseyev maxale at gmail.com
Sat Oct 3 15:08:29 CEST 2015

Just a brief update -- there are no primes among first 77,000 terms.


On Tue, Sep 29, 2015 at 9:18 PM, Neil Sloane <njasloane at gmail.com> wrote:
> To Seq Fans:
> Consider the sequence with nth term equal to the
> concatenation of the decimal numbers 1234...n (https://oeis.org/A007908).
> When is the first prime? The comments in A007908 say
> that there should be infinitely many primes, and that there
> are no primes among the first 64000 terms.
> If you would like to help with this search, you could leave a comment
> in A007908 saying that there are no primes among terms X through Y,
> or, of course, that n = Z gives a (probable) prime, which would be
> pretty exciting.
> Best regards
> Neil
> Neil J. A. Sloane, President, OEIS Foundation.
> 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
> Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
> Phone: 732 828 6098; home page: http://NeilSloane.com
> Email: njasloane at gmail.com
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