This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A141890 #14 Sep 08 2022 08:45:35 %S A141890 5,47,89,131,173,257,383,467,509,593,677,719,761,887,929,971,1013, %T A141890 1097,1181,1223,1307,1433,1559,1601,1811,1979,2063,2273,2357,2399, %U A141890 2441,2609,2693,2777,2819,2861,2903,3323,3407,3449,3491,3533,3617,3659,3701,3911 %N A141890 Primes congruent to 5 mod 21. %H A141890 Vincenzo Librandi, <a href="/A141890/b141890.txt">Table of n, a(n) for n = 1..1000</a> %F A141890 a(n) ~ 12n log n. - _Charles R Greathouse IV_, Jul 03 2016 %t A141890 Select[Range[5,5000,21],PrimeQ] (* _Vladimir Joseph Stephan Orlovsky_, Apr 03 2011*) %t A141890 Select[Prime[Range[600]],Mod[#,21]==5&] (* _Harvey P. Dale_, Jan 30 2021 *) %o A141890 (Magma) [p: p in PrimesUpTo(6000) | p mod 21 eq 5 ]; // _Vincenzo Librandi_, Aug 16 2012 %o A141890 (PARI) is(n)=isprime(n) && n%21==5 \\ _Charles R Greathouse IV_, Jul 03 2016 %Y A141890 Cf. A000040, A124826. %K A141890 nonn,easy %O A141890 1,1 %A A141890 _N. J. A. Sloane_, Jul 11 2008