[seqfan] Re: A174397 and primes with negative value.
Maximilian Hasler
maximilian.hasler at gmail.com
Sat Mar 20 13:25:30 CET 2010
Well as long as almost all terms are positive, and an explicative
remark is added, one might consider it as tolerable,
as in your seqs
A103802 A103803 A103804 A103805 A103806 A103807
but I must admit that I don't see well the motivation for the
particular case of chosen offsets (9, 15, 21, 27, 33, and the
combination "+/- 27 and +/- 33") in these sequences
(e.g. A103807 Primes p such that p, 2p+/-27 and 2p+/-33 are all primes.)
maybe adding a link to other similar existing sequences could explain
the motivation ?
As to
%N A050267 Primes of the form 47*n^2-1701*n+10181.
and similar sequences, the terms are not correct since according to
the definition, this is a list of numbers with some property, and they
must be listed in increasing size.
In the concrete case at hand, the sequence should read :
A050267 =
-5209, -5171, -5153, -5039, -5003, -4813, -4759, -4493, -4421, -4079,
-3989, -3571, -3463, -2969, -2843, -2273, -2129, -1483, -1321, -599,
-419, 379, 577, 1451, 1667, 2617, 2851, 3877, 4129, 5231, 5501, 6679,
6967, 8221, 8527, ...
then decide whether / why "n" should take only nonnegative values.
Maximilian
On Sat, Mar 20, 2010 at 1:03 PM, zak seidov <zakseidov at yahoo.com> wrote:
> And another case of negative primes
>
> %N A050267 Primes of the form 47*n^2-1701*n+10181.
>
> %V A050267 10181,8527,6967,5501,4129,2851,1667,577,-419,-1321,-2129,-2843,-3463,
> -3989,-4421,
> %W A050267 -4759,-5003,-5153,-5209,-5171,-5039,-4813,-4493,-4079,-3571,-2969,-2273,
> -1483,-599,
> %X A050267 379,1451,2617,3877,5231,6679,8221,9857,11587,13411,15329,17341,19447
>
>
> Zak
>
>
> ----- Original Message ----
> From: zak seidov <zakseidov at yahoo.com>
> To: seqfaneu <seqfan at seqfan.eu>
> Sent: Sat, March 20, 2010 1:58:12 PM
> Subject: [seqfan] Re: A174397 and primes with negative value.
>
> But we have several "negative primes" in OEIS:
>
> A088005 Numbers whose abundance is either a positive or a negative prime number.
>
> A125211 a(n) = total number of positive and negative primes of the form k! - n.
>
> A125212 a(n) = numbers n such that no positive and no negative prime exists of the form k! - n; or A125211(n) = 0.
>
> A088006 Abundance values which are either positive or negative prime numbers.
>
> A002143 (see rf. ET Ordman)
>
> A125236 (see %e )
>
> A103807 Primes p such that p, 2p+/-27 and 2p+/-33 are all primes. (my sequence ?!)
>
> Remove or not remove - that is the Q ;-)
>
> Zak
>
>
>
>
>
>
> ----- Original Message ----
> From: N. J. A. Sloane <njas at research.att.com>
> To: seqfan at list.seqfan.eu
> Cc: 4vladimir at gmail.com
> Sent: Sat, March 20, 2010 6:21:21 AM
> Subject: [seqfan] Re: A174397 and primes with negative value.
>
> Yes, in the OEIS primes are positive. I'm going to reject this sequence:
>
> %I A174397
> %S A174397 29,2,47,241,1181,4691,15307,24023,29401,42437,117043,226231,
> %T A174397 273827,299941,703883,1441523,2246501,2569691,3441121,4328773,
> %U A174397 5733173,6329387,8362973,10791191,12006223,13649033,14703167
> %V A174397 29,2,-47,-241,-1181,-4691,-15307,-24023,-29401,-42437,-117043,-226231,
> %W A174397 -273827,-299941,-703883,-1441523,-2246501,-2569691,-3441121,-4328773,
> %X A174397 -5733173,-6329387,-8362973,-10791191,-12006223,-13649033,-14703167
> %N A174397 Primes of the form p=(n+2)^3-(n+1)^3-n^3.
> %Y A174397 Select[Table[(n+2)^3-(n+1)^3-n^3, {n, 6!}], PrimeQ[ # ]&]
> %Y A174397 Adjacent sequences: A174394 A174395 A174396 this_sequence A174398 A174399 A174400
> %K A174397 nonn,new
> %O A174397 1,1
> %A A174397 Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 18 2010
>
>
> Neil
>
>
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