# [seqfan] Re: A128471

zak seidov zakseidov at yahoo.com
Sun Sep 5 14:49:55 CEST 2010

```All this is great,
but kw "less"'d be OK (IMHO).

--- On Sun, 9/5/10, Richard Mathar <mathar at strw.leidenuniv.nl> wrote:

> From: Richard Mathar <mathar at strw.leidenuniv.nl>
> Subject: [seqfan] Re: A128471
> To: seqfan at seqfan.eu
> Date: Sunday, September 5, 2010, 8:20 AM
>
> http://list.seqfan.eu/pipermail/seqfan/2010-September/005951.html
> is correct. My humble proposal is to go with
>
> %I A128471
> %S A128471
> 7,37,67,97,127,157,187,217,247,277,307,337,367,397,427,457,487,517,547,
> %T A128471
> 577,607,637,667,697,727,757,787,817,847,877,907,937,967,997,1027,1057,
> %U A128471
> 1087,1117,1147,1177,1207,1237,1267,1297,1327,1357,1387,1417,1447,1477
> %N A128471 30*n+7.
> %C A128471 30*n+7 -/+ 2 is a multiple of 3 or 5. For n >
> 0, this number is not prime.
> %C A128471 So with the exception of a(0), no a(n) is a
> member of a twin prime pair.
> %H A128471 <a href="http://home.hccnet.nl/a.w.m.van.der.horst/hcc96.txt">Counting
> Twin Primes</a>
> %H A128471 <a href="Sindx_Rea.html#recLCC">Index to
> sequences with linear recurrences with constant
> coefficients</a>, signature (2,-1).
> %F A128471 a(n) = 2*a(n-1)-a(n-2). [V. Librandri
> (vincenzo.librandi(AT)tin.it), Sep 05 2010]
> %F A128471 G.f. (7+23*x)/(x-1)^2. [R. J. Mathar, Sep 05
> 2010]
> %o A128471 (PARI) A128471(n)={ return(30*n+7) ; }
> %o A128471 for(n=0,30,print1(A128471(n)",")) ; /* R. J.
> Mathar, Sep 05 2010 */
> %Y A128471 Adjacent sequences: A128468 A128469 A128470
> this_sequence A128472 A128473 A128474
> %Y A128471 Sequence in context: A032588 A123084 A123085
> this_sequence A168003 A132231 A104915
> %K A128471 easy,nonn
> %O A128471 0,1
> %A A128471 Cino Hilliard (hillcino368(AT)hotmail.com), May
> 06 2007
> %E A128471 Comment clarified by R. Israel, offset set to
> zero by R. J. Mathar, Sep 05 2010
>
>
>
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>

```