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Numbers k such that 8*k+3 and 8*k+7 are primes.
2

%I #11 Mar 19 2020 06:53:46

%S 2,5,8,20,38,47,62,80,92,107,110,113,185,197,233,260,275,293,317,332,

%T 335,338,377,395,398,488,500,653,668,722,740,755,818,863,905,950,962,

%U 965,1052,1055,1067,1097,1100,1193,1202,1217,1223,1235,1262,1280,1283

%N Numbers k such that 8*k+3 and 8*k+7 are primes.

%H Amiram Eldar, <a href="/A139407/b139407.txt">Table of n, a(n) for n = 1..10000</a>

%t a = {}; Do[If[PrimeQ[8 n + 3] && PrimeQ[8 n + 7], AppendTo[a, n]], {n, 1, 1000}]; a

%t Select[Range[1500],And@@PrimeQ[8 # +{3,7}]&] (* _Harvey P. Dale_, Mar 24 2011 *)

%Y Cf. A125821, A125822, A139402, A139404, A139405, A139406.

%K nonn

%O 1,1

%A _Artur Jasinski_, Apr 19 2008