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 A128471 30*n+7. 2

%I

%S 7,37,67,97,127,157,187,217,247,277,307,337,367,397,427,457,487,517,

%T 547,577,607,637,667,697,727,757,787,817,847,877,907,937,967,997,1027,

%U 1057,1087,1117,1147,1177,1207,1237,1267,1297,1327,1357,1387,1417,1447,1477

%N 30*n+7.

%C 30*n+7 -/+ 2 is a multiple of 3 or 5. For n > 0, this number is not prime. So with the exception of a(0), no a(n) is a member of a twin prime pair.

%C Except for 7, these numbers cannot be written as sum or difference of two primes. [Arkadiusz Wesolowski, Jan 08 2012]

%H <a href="http://home.hccnet.nl/a.w.m.van.der.horst/hcc96.txt">Counting Twin Primes</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

%F a(n) = 2*a(n-1)-a(n-2). [_Vincenzo Librandi_, Sep 05 2010]

%F G.f. (7+23*x)/(1-x)^2. [R. J. Mathar, Sep 05 2010]

%t Range[7,7000,30] (* _Vladimir Joseph Stephan Orlovsky_, Jun 18 2011 *)

%o (PARI) A128471(n)={ return(30*n+7) ; }

%o for(n=0,30,print1(A128471(n)",")) ; /* R. J. Mathar, Sep 05 2010 */

%K easy,nonn

%O 0,1

%A _Cino Hilliard_, May 06 2007

%E Comment clarified by R. Israel, offset set to zero by R. J. Mathar, Sep 05 2010

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Last modified April 11 03:12 EDT 2021. Contains 342886 sequences. (Running on oeis4.)