[seqfan] Re: A128471
israel at math.ubc.ca
Sun Sep 5 10:16:48 CEST 2010
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 that
cannot be part of a twin prime pair" should not be part of the title.
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 twin
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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