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 A200879 #8 Jul 08 2023 21:00:17 %S A200879 1,3,9,11,33,41,99,101,123,251,271,303,369,451,753,813,909,1111,1353, %T A200879 2259,2439,2761,2981,3333,3541,4059,4141,5051,8283,8943,9091,9999, %U A200879 10291,10623,11111,12423,15153,21401,24849,25351,25601,26829,27273,27371,27961 %N A200879 Numbers n such that 10^n - 1 divides 10^(10^100) - 10. %H A200879 Dario A. Alpern, <a href="https://www.alpertron.com.ar/googolm.pl">Known prime factors of Googolplex - 10</a> %H A200879 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Googolplex.html">Googolplex</a> %t A200879 Prepend[Select[Range[3, 3000, 2], PowerMod[10, 10^100, 10^# - 1] == 10 &], 1] %Y A200879 A200861 is a subsequence. %K A200879 fini,nonn %O A200879 1,2 %A A200879 _Arkadiusz Wesolowski_, Nov 23 2011