[seqfan] Re: Numbers such that the n-th and (n+1)st terms are the successors of prime numbers and primes themselves and n+1 > n

David Applegate david at research.att.com
Tue Nov 25 20:26:05 CET 2014


While poking around at this, I came across A075321,A075322, and A075323.
These are based on "pair the odd primes so that the k-th pair is (p, p+2k)"
The three sequences are the first in the pair, the second in the pair, and
the pairs in order.

As I read the description, every term should be prime.  However, when I look
at the sequence, I see 45, 55, 99, 115, 169, 201, 235, all of which are
composite.  Are the sequences wrong, or does the definition need to be cleaned
up?

-Dave

> From seqfan-bounces at list.seqfan.eu Tue Nov 25 13:51:54 2014
> Date: Tue, 25 Nov 2014 13:50:58 -0500
> From: Neil Sloane <njasloane at gmail.com>
> To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> Subject: [seqfan] Re: Numbers such that the n-th and (n+1)st terms are the  successors of prime numbers and primes themselves and n+1 > n

> That one (A147513) is certainly a mess.  If no one has a better idea, let's
> leave the terms intact, but give it keywords uned,obsc,unkn !

> 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

> On Tue, Nov 25, 2014 at 1:30 PM, Charles Greathouse <
> charles.greathouse at case.edu> wrote:

> > Does anyone understand the definition of A147513? The terms start
> > 3, 5, 7, 11, 13, 19, 23, 31, 37, 47, 51
> > and no other information is given.
> >
> > Charles Greathouse
> > Analyst/Programmer
> > Case Western Reserve University
> >
> > _______________________________________________
> >
> > Seqfan Mailing list - http://list.seqfan.eu/
> >

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