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 A167020 #11 Sep 08 2022 08:45:48
%S A167020 1,1,1,1,1,0,1,1,1,1,0,1,0,1,1,0,1,1,1,0,0,1,1,0,1,0,0,1,1,1,0,1,1,0,
%T A167020 0,0,0,1,1,1,0,1,1,1,1,0,1,0,1,0,0,1,1,0,0,0,0,1,1,1,0,0,0,1,1,0,1,0,
%U A167020 0,1,0,1,0,1,1,0,1,1,0,1,0,1,0,1,1,0,1,0,0,0,0,0,1,1,1,0,0,1,1,1,0,0,1,0,0
%N A167020 a(n) = 1 iff 6n-1 is prime.
%H A167020 Vincenzo Librandi, <a href="/A167020/b167020.txt">Table of n, a(n) for n = 1..5000</a>
%H A167020 <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%e A167020 a(5) = 1 because 6*5-1 is prime, a(6) = 0 since 6*6-1 is composite.
%t A167020 Table[If[PrimeQ[6 n - 1], 1, 0], {n, 100}] (* _Vincenzo Librandi_, Jan 19 2019 *)
%o A167020 (PARI) a(n) = isprime(6*n-1); \\ _Michel Marcus_, Jan 19 2019
%o A167020 (Magma) [IsPrime(6*n-1) select 1 else 0: n in[1..100]]; // _Vincenzo Librandi_, Jan 19 2019
%Y A167020 Cf. A024898, A167021.
%K A167020 nonn
%O A167020 1,1
%A A167020 _Washington Bomfim_, Oct 27 2009