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 A239063 #32 Oct 30 2021 09:13:03
%S A239063 1,2,4,6,8,10,12,16,18,20,24,30,32,34,36,40,42,46,48,50,54,60,64,68,
%T A239063 72,78,80,82,84,90,94,96,98,100,102,108,110,114,120,126,128,136,144,
%U A239063 150,156,160,162,164,168,170,176,180,186,188,192,194,198,200,204
%N A239063 Numbers k for which the equation x^x == 1 (mod k) has x=1 as its only solution such that 1 <= x <= k.
%C A239063 A number k belongs to this sequence if and only if for all primes p|k and for all primes q|p-1, q divides k. - _Bernat Pagès Vives_, Oct 30 2021
%H A239063 Giovanni Resta, <a href="/A239063/b239063.txt">Table of n, a(n) for n = 1..10000</a>
%H A239063 Art of Problem Solving, <a href="https://artofproblemsolving.com/community/c487h563364p3289941">OMO Fall 2013 Solutions, problem 22</a>
%t A239063 gg1[n_] := Sum[If[Mod[x^x, n] == Mod[1, n], 1, 0],{x,1,n}]; Select[Range[100], gg1[#] == 1 &]
%Y A239063 Cf. A239061.
%K A239063 nonn
%O A239063 1,2
%A A239063 _José María Grau Ribas_, Mar 09 2014