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 A057351 #20 Jan 08 2022 03:50:46 %S A057351 1,2,26,338,2054,4394,13282,26702,46306,57122,59566,162266,221446, %T A057351 347126,404293,742586,760318,1301638,2031406,2109458,2857114,4512638, %U A057351 4752982,8340826,8634886,9653618,10066654,12819014,19012162,21263026,25885054,27422954,34901542 %N A057351 Numbers k that divide 4^k + 3^k + 1. %H A057351 Michael S. Branicky, <a href="/A057351/b057351.txt">Table of n, a(n) for n = 1..82</a> %t A057351 Select[ Range[ 10^6 ], Mod[ PowerMod[ 4, #, # ] + PowerMod[ 3, #, # ] + 1, # ] == 0 & ] %Y A057351 Cf. A074506. %K A057351 nonn,hard %O A057351 1,2 %A A057351 _Robert G. Wilson v_, Sep 22 2000 %E A057351 a(18) from _Hugo Pfoertner_, Jan 05 2022 %E A057351 a(19)-a(33) from _Michael S. Branicky_, Jan 06 2022