[seqfan] Re: A128471

vincenzo.librandi at tin.it vincenzo.librandi at tin.it
Sun Sep 5 11:38:52 CEST 2010

 Hello Dear Robert

Thank you 
for your assistance.

course it can also be as you say.


Date: Sun, 5 Sep 2010 01:16:48 -0700 (PDT)
From: Robert Israel <israel at math.ubc.ca>
Subject: [seqfan] Re: A128471
To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
Message-ID: <Pine.GSO.4.64.1009050111210.18691 at hilbert.math.ubc.ca>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

>You could just as well say a(n) = a(n-1)+30, with a(1)=7.
>But I think the "or with the exception of the first entry, numbers
>cannot be part of a twin prime pair" should not be part of the
>Maybe at most a comment, though even this is rather silly: there are
>lots of numbers not in the sequence that also can't be part of a
>prime pair.

Robert Israel israel at math.ubc.ca
Department of Mathematics http://www.math.ubc.ca/~israel 
University of British Columbia Vancouver, BC, Canada

On Sat, 4 Sep 2010, vincenzo.librandi at tin.it wrote:

> Dear seqfqns
> formula of A128471:
> a(n)=2*a(n-1)-a(n-2), with (a(1)=7 a(2)=37)
> Ex: a(3)=2*37-7=67; a(4)=2*67-37=97; a(5)=2*97-67=127.
> Regards, Vincenzo

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