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 A230743 #13 Mar 02 2014 08:15:38
%S A230743 4,9,115,720,2476,42471,4765,1788961,3780956,51872200,310486445,
%T A230743 1142532559,18483128564,4205436520,799862636324,1584162310079,
%U A230743 23384002313285,133802323596440,526151093402156,8041209044472401,2783579583540395,357525366658772391
%N A230743 Values of x such that x^2 + y^2 = 41^n with x and y coprime and 0 < x < y.
%C A230743 The corresponding y-values are in A230744.
%H A230743 Vincenzo Librandi, <a href="/A230743/b230743.txt">Table of n, a(n) for n = 1..200</a>
%e A230743 a(3)=115 because 115^2+236^2=68921=41^3.
%t A230743 Table[Select[PowersRepresentations[41^n, 2, 2], CoprimeQ@@#&][[1, 1]], {n, 1, 40}] (* _Vincenzo Librandi_, Mar 02 2014 *)
%Y A230743 Cf. A009985, A230744, A188948, A230622, A230644, A230710, A230712.
%K A230743 nonn
%O A230743 1,1
%A A230743 _Colin Barker_, Oct 29 2013