%I #15 Sep 08 2022 08:45:35
%S 2,23,107,149,191,233,317,359,401,443,569,653,821,863,947,1031,1283,
%T 1367,1409,1451,1493,1619,1787,1871,1913,1997,2039,2081,2207,2333,
%U 2417,2459,2543,2711,2753,2837,2879,2963,3089,3257,3299,3467,3593,3677,3719,3761
%N Primes congruent to 2 mod 21.
%H Vincenzo Librandi, <a href="/A141888/b141888.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) ~ 12n log n. - _Charles R Greathouse IV_, Jul 02 2016
%t Select[Prime[Range[600]], Mod[#,21] == 2&] (* _Harvey P. Dale_, Jan 04 2011 *)
%o (Magma) [p: p in PrimesUpTo(4000) | p mod 21 eq 2 ]; // _Vincenzo Librandi_, Aug 16 2012
%o (PARI) is(n)=isprime(n) && n%21==2 \\ _Charles R Greathouse IV_, Jul 02 2016
%Y Cf. A000040.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_, Jul 11 2008
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