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 A177132 #16 Sep 08 2024 19:26:02
%S A177132 7,61,601,600000001,6000000001,6000000000000001,600000000000000000001,
%T A177132 600000000000000000000000001,600000000000000000000000000000000000001,
%U A177132 6000000000000000000000000000000000000000000001,600000000000000000000000000000000000000000000000000000000000000001
%N A177132 Primes of the form 6*10^n+1.
%H A177132 Makoto Kamada, <a href="https://stdkmd.net/nrr/6/60001.htm#prime">Prime numbers of the form 600...001</a>.
%t A177132 Select[Table[6*10^n+1,{n,0,70}],PrimeQ] (* _Harvey P. Dale_, Feb 22 2015 *)
%o A177132 (Magma) [a: n in [0..250]|IsPrime(a) where a is 6*10^n+1];
%Y A177132 Cf. A056805.
%K A177132 nonn
%O A177132 1,1
%A A177132 _Vincenzo Librandi_, Dec 10 2010