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 A177243 #8 Jun 06 2021 09:02:38
%S A177243 1,3,9,111,333,1467,6813,54279,84573,252081,607947,665667,1001001,
%T A177243 1110519,1823841,3003003,3129201,12914001,13785399,22161609,22957083,
%U A177243 37037037,41089203,49235049,64021761,92840751,108503721,111111111
%N A177243 Numbers k such that k^3 divides 10^(k^2) - 1.
%t A177243 Join[{1},Select[Range[1112*10^5],PowerMod[10,#^2,#^3]==1&]] (* _Harvey P. Dale_, Sep 10 2019 *)
%Y A177243 Cf. A127100 (k^2 divides 10^k-1), A014950 (k divides 10^k-1).
%K A177243 nonn
%O A177243 1,2
%A A177243 _Alexander Adamchuk_, May 06 2010