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 A230712 #12 Mar 02 2014 08:15:21
%S A230712 1,12,107,840,5646,27755,124158,462961,961686,5589325,102654282,
%T A230712 1025046359,8502347874,64101459205,356029844147,1681548425760,
%U A230712 7005476875681,21848430755052,2978524660427,772649642011800
%N A230712 Values of x such that x^2 + y^2 = 37^n with x and y coprime and 0 < x < y.
%C A230712 The corresponding y-values are in A230713.
%H A230712 Vincenzo Librandi, <a href="/A230712/b230712.txt">Table of n, a(n) for n = 1..200</a>
%e A230712 a(3)=107 because 107^2+198^2=50653=37^3.
%t A230712 Table[Select[PowersRepresentations[37^n, 2, 2], CoprimeQ@@#&][[1, 1]], {n, 1, 40}] (* _Vincenzo Librandi_, Mar 02 2014 *)
%Y A230712 Cf. A009981, A188948, A230622, A230644, A230710, A230713.
%K A230712 nonn
%O A230712 1,2
%A A230712 _Colin Barker_, Oct 28 2013