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Numbers k such that 8*k+1 and 8*k+7 are primes.
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%I #13 Mar 19 2020 06:54:41

%S 2,5,9,12,24,29,32,44,54,57,74,75,80,107,110,122,129,137,152,162,165,

%T 170,179,185,194,200,207,219,222,234,249,260,267,285,297,299,302,305,

%U 332,339,362,414,432,452,470,500,509,519,555,557,564,570,582,584,599

%N Numbers k such that 8*k+1 and 8*k+7 are primes.

%H Amiram Eldar, <a href="/A139405/b139405.txt">Table of n, a(n) for n = 1..10000</a>

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

%Y Cf. A017077, A004771.

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

%K nonn

%O 1,1

%A _Artur Jasinski_, Apr 19 2008