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 A141894 #20 Sep 08 2022 08:45:35 %S A141894 13,97,139,181,223,307,349,433,601,643,727,769,811,853,937,1021,1063, %T A141894 1231,1399,1483,1567,1609,1693,1777,1861,1987,2029,2113,2239,2281, %U A141894 2617,2659,2953,3037,3079,3121,3163,3331,3373,3457,3499,3541,3583,3709,3793,3877 %N A141894 Primes congruent to 13 mod 21. %H A141894 Vincenzo Librandi, <a href="/A141894/b141894.txt">Table of n, a(n) for n = 1..1000</a> %F A141894 a(n) ~ 12n log n. - _Charles R Greathouse IV_, Jul 01 2016 %t A141894 Select[Range[13,5000,21],PrimeQ] (* _Vladimir Joseph Stephan Orlovsky_, Apr 04 2011 *) %o A141894 (Magma) [ p: p in PrimesUpTo(5000) | p mod 21 eq 13 ]; // _Vincenzo Librandi_, Apr 05 2011 %o A141894 (PARI) is(n)=isprime(n) && n%21==13 \\ _Charles R Greathouse IV_, Jul 01 2016 %Y A141894 Cf. A000040, A124826. %K A141894 nonn,easy %O A141894 1,1 %A A141894 _N. J. A. Sloane_, Jul 11 2008