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 A003572 #16 Oct 22 2023 16:20:30
%S A003572 1,4,2,5,6,16,4,11,3,28,8,12,18,8,10,23,20,52,6,29,30,12,16,35,18,30,
%T A003572 4,41,42,88,22,36,42,100,6,53,20,112,28,48,10,100,32,65,22,136,12,15,
%U A003572 12,148,18,60,78,66,8,83,16,172
%N A003572 Order of 3 mod 3n+2.
%H A003572 Jinyuan Wang, <a href="/A003572/b003572.txt">Table of n, a(n) for n = 0..10000</a>
%p A003572 with(numtheory): f := n->order(3,3*n+2);
%t A003572 Table[MultiplicativeOrder[3, 3*n + 2], {n, 0, 57}] (* _Jinyuan Wang_, Feb 16 2019 *)
%o A003572 (PARI) a(n) = znorder(Mod(3, 3*n+2)); \\ _Michel Marcus_, Feb 16 2019
%o A003572 (GAP) List([0..60],n->OrderMod(3,3*n+2)); # _Muniru A Asiru_, Feb 16 2019
%Y A003572 Cf. A002326, A003571, A003574, A217852.
%K A003572 nonn
%O A003572 0,2
%A A003572 _N. J. A. Sloane_