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 A136679 #8 Mar 27 2021 01:00:54
%S A136679 0,0,0,9,0,16,24,45,56,48,80,137,96,144,128,315,192,302,288,425,312,
%T A136679 400,440,621,544,528,728,969,672,704,840,1451,880,960,984,2021,1152,
%U A136679 1296,1248,1901,1440,1504,1680,2569,2024,1936,2024,3387,2400,2524,2240,3561
%N A136679 a(n) is the number of ordered solutions (x,y,z) to x^2 + y^2 == z^2 mod n with 1 <= x,y,z <= n-1.
%C A136679 Record values: 0, 9, 16, 24, 45, 56, 80, 137, 144, 315, 425, 440, 621, 728, 969, 1451, 2021, 2569, 3387, 3561, 4077, 4649, 6871, 8441, 9915, 10605, 11977, 14507, 16129, 20069, 20283, 22089, 28823, 41555, 41643, 43017, 51515, 56069, 65239, 65989, 72123, ....
%H A136679 Robert G. Wilson v, <a href="/A136679/b136679.txt">Table of n, a(n) for n = 1..215.</a>.
%e A136679 a(4)=9 because {1, 2, 1}, {1, 2, 3}, {2, 1, 1}, {2, 1, 3}, {2, 2, 2}, {2, 3, 1}, {2, 3, 3}, {3, 2, 1}, {3, 2, 3} are solutions for n=4.
%t A136679 f[n_] := Block[ {c = 0}, Do[ If[ Mod[x^2 + y^2, n] == Mod[z^2, n], c++ ], {x, n - 1}, {y, n - 1}, {z, n - 1}]; c]; Array[f, 52]
%Y A136679 Cf. A137401.
%K A136679 nonn
%O A136679 1,4
%A A136679 _Robert G. Wilson v_, Apr 12 2008