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%I #22 Jan 26 2023 10:03:18
%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 a(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 _Robert Israel_, offset set to zero by _R. J. Mathar_, Sep 05 2010
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