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 A200861 #35 Jul 08 2023 21:00:06
%S A200861 3,3,11,41,101,251,271,3541,5051,9091,21401,25601,27961,60101,7019801,
%T A200861 182521213001,14103673319201,78875943472201,1680588011350901
%N A200861 Prime factors of 10^100 - 1.
%C A200861 Is this sequence the same as "Primes p such that 10^p - 1 divides 10^(10^100) - 10"?
%H A200861 Dario A. Alpern, <a href="https://www.alpertron.com.ar/googolm.pl">Known prime factors of Googolplex - 10</a>
%H A200861 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Googol.html">Googol</a>
%p A200861 sort(map(i-> i[1]$i[2], ifactors(10^100-1)[2]))[]; # _Alois P. Heinz_, Jan 27 2023
%t A200861 Join[{3}, Transpose[FactorInteger[10^100 - 1]][[1]]]
%Y A200861 Subsequence of A178070 except for 3.
%K A200861 fini,full,nonn
%O A200861 1,1
%A A200861 _Arkadiusz Wesolowski_, Nov 23 2011
%E A200861 Name changed by _T. D. Noe_ and _Arkadiusz Wesolowski_, Nov 29 2011