Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #16 Sep 24 2024 03:12:23
%S 2,4,12,22,32,34,64,74,92,102,152,204,274,284,292,362,432,474,482,494,
%T 554,564,594,622,624,664,694,712,792,894,902,932,1054,1084,1152,1154,
%U 1282,1384,1504,1594,1742,1804,1812,1882,1884,1912,2182,2274,2402,2584
%N Numbers k such that 3k+1, 3k+5 and 3k+7 are all prime.
%H Seiichi Manyama, <a href="/A062767/b062767.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[2600], PrimeQ[3#+1] && PrimeQ[3#+5] && PrimeQ[3#+7] &] (* _Stefano Spezia_, Sep 23 2024 *)
%o (PARI) j=[]; for(n=1,10000, if(isprime(3*n+1) && isprime(3*n+5) && isprime(3*n+7), j=concat(j,n))); j
%K nonn
%O 1,1
%A _Jason Earls_, Jul 17 2001