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 A062174 #14 Jun 01 2018 06:54:27
%S A062174 0,1,0,3,1,3,1,3,0,3,1,3,1,3,9,11,1,9,1,7,9,3,1,3,6,3,0,27,1,3,1,11,9,
%T A062174 3,4,27,1,3,9,27,1,33,1,27,36,3,1,27,43,33,9,27,1,27,4,3,9,3,1,27,1,3,
%U A062174 9,43,16,45,1,27,9,13,1,27,1,3,69,27,25,9,1,27,0,3,1,75,81,3,9,75,1,63
%N A062174 a(n) = 3^(n-1) mod n.
%H A062174 Harry J. Smith, <a href="/A062174/b062174.txt">Table of n, a(n) for n = 1..1000</a>
%H A062174 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%t A062174 Table[PowerMod[3,n-1,n],{n,90}] (* _Harvey P. Dale_, Oct 03 2012 *)
%o A062174 (PARI) { for (n=1, 1000, write("b062174.txt", n, " ", 3^(n - 1)%n) ) } \\ _Harry J. Smith_, Aug 02 2009
%Y A062174 Cf. A062172.
%K A062174 nonn
%O A062174 1,4
%A A062174 _Henry Bottomley_, Jun 12 2001