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 A067602 #23 Sep 08 2022 08:45:05
%S A067602 0,2,7,17,58,209,316,1580,3526,4508,22540,112700,209206,1046030,
%T A067602 447181,11801843,30311401,108510284,155130931,775654655,391488874,
%U A067602 1957444370,9787221850,48936109250,150537367423,470257300634,656709284284
%N A067602 5^n reduced modulo 3^n.
%H A067602 Harvey P. Dale, <a href="/A067602/b067602.txt">Table of n, a(n) for n = 0..1000</a>
%p A067602 a:=n->5^n mod(3^(n)): seq(a(n), n=0..26); # _Zerinvary Lajos_, Feb 15 2008
%t A067602 Table[Mod[5^n, 3^n], {n, 0, 30}] (* _Vincenzo Librandi_, Jun 24 2015 *)
%t A067602 Table[PowerMod[5,n,3^n],{n,0,30}] (* _Harvey P. Dale_, Oct 28 2019 *)
%o A067602 (PARI) for(n=0,50,print1(lift(Mod(5^n,3^n)), ", "))
%o A067602 (PARI) a(n)= lift(Mod(5, 3^n)^n); \\ _Michel Marcus_, Jun 24 2015
%o A067602 (Sage) [power_mod(5,n,3^n)for n in range(0,27)] # _Zerinvary Lajos_, Nov 28 2009
%o A067602 (Magma) [5^n mod 3^n: n in [0..30]]; // _Vincenzo Librandi_, Jun 24 2015
%K A067602 nonn
%O A067602 0,2
%A A067602 _Benoit Cloitre_, Jan 31 2002