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 A276671 #31 Oct 05 2021 21:18:57
%S A276671 1,2929,9742277641,23341869101,15092205901438895,16311037042239935
%N A276671 Positive integers k such that 3^k == 2 (mod k).
%C A276671 No other terms below 2*10^16. A larger term: 31744873758348589012852097851.
%t A276671 Join[{1}, Select[Range[10000], PowerMod[3, #, #] == 2 &]] (* _Alonso del Arte_, Oct 11 2016 *)
%o A276671 (PARI) isok(n) = Mod(3, n)^n == Mod(2, n); \\ _Dmitry Ezhov_, Sep 28 2016
%Y A276671 Cf. A015973, A067945, A015949, A055686, A242865, A234535, A234536, A050259.
%K A276671 nonn,more,hard
%O A276671 1,2
%A A276671 _Max Alekseyev_, Oct 05 2016
%E A276671 Order of terms corrected by _Felix Fröhlich_, Oct 06 2016
%E A276671 a(5)-a(6) from _Sergey Paramonov_, Oct 03 2021