%I #11 Sep 08 2022 08:45:36

%S 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 23 mod 42.

%H Vincenzo Librandi, <a href="/A142244/b142244.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[1500]],MemberQ[{23},Mod[#,42]]&] (* _Vincenzo Librandi_, Aug 24 2012 *)

%t Select[Range[23,4000,42],PrimeQ] (* _Harvey P. Dale_, Dec 18 2013 *)

%o (Magma) [p: p in PrimesUpTo(4000) | p mod 42 eq 23 ]; // _Vincenzo Librandi_, Aug 24 2012

%o (PARI) is(n)=isprime(n) && n%42==23 \\ _Charles R Greathouse IV_, Jul 02 2016

%Y Cf. A000040.

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_, Jul 11 2008