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A155722 Numbers k such that 2*k + 9 is prime.

%I A155722 #45 Jun 30 2025 14:16:05
%S A155722 1,2,4,5,7,10,11,14,16,17,19,22,25,26,29,31,32,35,37,40,44,46,47,49,
%T A155722 50,52,59,61,64,65,70,71,74,77,79,82,85,86,91,92,94,95,101,107,109,
%U A155722 110,112,115,116,121,124,127,130,131,134,136,137,142,149,151,152,154,161,164
%N A155722 Numbers k such that 2*k + 9 is prime.
%C A155722 Subsequence of A001651; A011655(a(n)) = 1. - _Reinhard Zumkeller_, Jul 09 2010
%C A155722 One less than the associated entry in A105760, two less than in A089038, three less than in A067076. - _R. J. Mathar_, Jan 05 2011
%H A155722 Vincenzo Librandi, <a href="/A155722/b155722.txt">Table of n, a(n) for n = 1..1000</a>
%t A155722 (Prime[Range[5, 100]] - 9)/2 (* _Vladimir Joseph Stephan Orlovsky_, Feb 08 2010 *)
%t A155722 Select[Range[0, 200], PrimeQ[2 # + 9]&] (* _Vincenzo Librandi_, Sep 24 2012 *)
%o A155722 (Magma) [n: n in [0..200] | IsPrime(2*n+9)]; // _Vincenzo Librandi_, Sep 24 2012
%o A155722 (PARI) is(n)=isprime(2*n+9) \\ _Charles R Greathouse IV_, Jul 12 2016
%o A155722 (Sage) [n for n in (0..200) if is_prime(2*n+9) ] # _G. C. Greubel_, May 21 2019
%o A155722 (GAP) Filtered([0..200], k-> IsPrime(2*k+9)); # _G. C. Greubel_, May 21 2019
%Y A155722 Cf. A155723, A155724.
%Y A155722 Numbers h such that 2*h + k is prime: A005097 (k=1), A067076 (k=3), A089038 (k=5), A105760 (k=7), this seq (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19).
%K A155722 nonn,easy
%O A155722 1,2
%A A155722 _Vincenzo Librandi_, Jan 25 2009
%E A155722 Edited by _N. J. A. Sloane_, Jun 23 2010
%E A155722 Definition clarified by _Zak Seidov_, Jul 11 2014