[seqfan] Re: New sequence
njasloane at gmail.com
Thu Apr 6 03:19:56 CEST 2017
MFH said: so I wonder whether the sequence a(n)/2 should also be submitted.
NJAS says: Yes, definitely!
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 Wed, Apr 5, 2017 at 8:10 PM, M. F. Hasler <seqfan at hasler.fr> wrote:
> On Wed, Apr 5, 2017 at 5:22 PM, Graeme McRae <graememcrae at gmail.com> wrote:
>> for all possible primes p1, p2 such that p1+p2=E,
>> neither E+p1 nor E+p2 is prime.
>> The first few terms I found were:
>> 4, 6, 28, 38, 52, 58, 62, 68, 74, 80, 82, 88, 94, 98, 112, 118, 122, 124,
>> 128, 136...
> I searched for it in OEIS, and did not find it.
> I submitted https://oeis.org/draft/A284919
> including PARI code based on Charles' proposal,
> but not Graeme McRae's comment on the probably finite "for all" (or: no...)
> (cf below: you are invited to add it, conveniently rephrased).
> I also chose to include the two initial terms 0 and 2 which may be arguable
> but may affect search results only in a positive sense.
> Looking at other Goldbach related sequences, they often use n where E=2n,
> so I wonder whether the sequence a(n)/2 should also be submitted.
>> I also looked for even numbers such that *all* the values E+pn are prime.
>> The only such even numbers I found smaller than 1000 were 8 and 12. In
>> fact, the only even numbers smaller than 1000 such that all but one of the
>> values E+pn are prime are 8, 12, 18, 24, and 30. I wonder if these
>> sequences are finite.
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