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 A070081 #34 Oct 04 2021 08:17:25
%S A070081 1,2,2,3,2,3,4,3,3,4,3,5,4,3,4,5,4,4,6,5,4,5,4,6,5,4,5,7,6,5,6,4,5,5,
%T A070081 7,6,5,6,5,8,7,6,7,5,6,5,6,8,7,6,7,5,6,6,9,8,7,8,6,7,5,6,7,6,9,8,7,8,
%U A070081 6,7,6,7,10,9,8,9,7,8,6,7,8,6,7,7,10,9,8,9,7
%N A070081 Middle side of integer triangles [A070080(n) <= a(n) <= A070082(n)], sorted by perimeter, sides lexicographically ordered.
%H A070081 G. C. Greubel, <a href="/A070081/b070081.txt">Table of n, a(n) for the first 55 rows, flattened</a>
%H A070081 Reinhard Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a>
%F A070081 a(n) = A070083(n) - A070080(n) - A070082(n).
%t A070081 m = 55 (* max perimeter *);
%t A070081 sides[per_] := Select[Reverse /@ IntegerPartitions[per, {3}, Range[ Ceiling[per/2]]], #[[1]] < per/2 && #[[2]] < per/2 && #[[3]] < per/2&];
%t A070081 triangles = DeleteCases[Table[sides[per], {per, 3, m}], {}] // Flatten[#, 1]& // SortBy[Total[#] m^3 + #[[1]] m^2 + #[[2]] m + #[[1]]&];
%t A070081 triangles[[All, 2]] (* _Jean-François Alcover_, Jul 09 2017 *)
%Y A070081 Cf. A046129, A055593, A069595, A069594, A069598.
%Y A070081 Cf. A070080, A070082, A070083, A070084, A070085, A070086.
%K A070081 nonn
%O A070081 1,2
%A A070081 _Reinhard Zumkeller_, May 05 2002