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%I #13 Jun 27 2024 22:25:47
%S 3,6,18,21,30,33,51,63,81,90,96,105,135,138,153,156,165,168,186,216,
%T 243,261,270,300,336,363,375,378,411,426,441,453,495,510,531,543,576,
%U 585,606,615,618,648,651,723,726,741,765,798,810,828,831,846,861,891,930
%N Numbers k such that 2*k+1 and 6*k+1 are both primes of the form 6*m+1.
%C All terms are divisible by 3. - _Robert Israel_, Jun 27 2024
%H Harvey P. Dale, <a href="/A174101/b174101.txt">Table of n, a(n) for n = 1..1000</a>
%e 3 is a term: 3*2 + 1 = 7 and 3*6 + 1 = 19 are primes congruent to 1 (mod 6). - _R. J. Mathar_, Apr 16 2010
%p select(k -> isprime(2*k+1) and isprime(6*k+1), 3*[$1..1000]); # _Robert Israel_, Jun 27 2024
%t Select[Range[1000],With[{c={2,6}#+1},AllTrue[c,PrimeQ]&&AllTrue[(c-1)/6, IntegerQ]&]] (* _Harvey P. Dale_, Aug 08 2022 *)
%Y Cf. A002476, A065091.
%K nonn
%O 1,1
%A _Juri-Stepan Gerasimov_, Mar 07 2010
%E More terms from _R. J. Mathar_, Apr 16 2010
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