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 A128394 #10 Jun 06 2021 06:03:15 %S A128394 1,13,2041,24355253,249302027,16772956369,39665616523,388885239223, %T A128394 2974921088191,3487599163841,61054982558011,200151688351277, %U A128394 473329801968959 %N A128394 Numbers k such that k^2 divides 14^k - 1. %C A128394 13 divides all except the first term. %Y A128394 Cf. A127103, A127104, A127105, A127106, A127107, A127102, A127101, A127100, A127092, A128405, A128393, A128395, A128396, A128397, A128398, A128399, A128400, A128401, A128402, A128403, A128404. %K A128394 more,nonn,less %O A128394 1,2 %A A128394 _Alexander Adamchuk_, Mar 01 2007 %E A128394 a(4)-a(5) from _Farideh Firoozbakht_, Mar 05 2007 %E A128394 a(6)-a(13) from _Max Alekseyev_, May 06 2010