A124408 - OEIS

%I #6 Aug 04 2019 05:40:06

%S 1,3,18,105,135,153,165,168,300,363,585,618,648,765,828,1110,1140,

%T 1278,1518,1530,1533,2130,2223,2400,2475,2613,2790,2925,3075,3180,

%U 3345,3420,3483,3810,3840,3843,3933,4008,4083,4095,4143,4260,4263,4323,4470,4545

%N Numbers k such that 2k+1, 4k+1 and 6k+1 are primes.

%H Jinyuan Wang, <a href="/A124408/b124408.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[4600], And @@ PrimeQ /@ ({2, 4, 6}*# + 1) &] (* _Ray Chandler_, Nov 20 2006 *)

%o (PARI) is(k) = sum(j = 1, 3, isprime(2*j*k+1)) == 3; \\ _Jinyuan Wang_, Aug 04 2019

%Y Cf. A005097, A005098, A024899, A123998, A124409, A124410, A124411, A071576.

%K nonn

%O 1,2

%A _Artur Jasinski_, Oct 31 2006