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 A024156 #8 Mar 01 2019 14:16:15
%S A024156 0,0,0,0,0,0,0,0,1,0,1,0,2,1,2,2,3,2,4,3,6,3,7,4,8,6,9,7,10,8,12,10,
%T A024156 15,11,16,13,18,15,19,17,21,19,25,21,28,22,30,25,32,28,35,31,38,33,41,
%U A024156 35,45,38,47,42,51,46,53,50,57,52,61,55,65,58,68,63,74,67,77,71,82,74,86,77,92,82,96,87
%N A024156 Number of integer-sided triangles with sides a,b,c, a<b<c, a+b+c=n that are obtuse.
%H A024156 Jean-François Alcover, <a href="/A024156/b024156.txt">Table of n, a(n) for n = 1..200</a>
%t A024156 r[n_] := Module[{a, b}, Reduce[a>1 && a<b && a + 2b < n && 2(a + b) > n && 2n(a + b) < 2a*b + n^2, {a, b}, Integers]];
%t A024156 a[n_] := Module[{rn = r[n]}, Which[rn === False, 0, rn[[0]] === And, 1, rn[[0]] === Or, Length[rn], True, Print["error: ", n, " ", rn]]];
%t A024156 Array[a, 84] (* _Jean-François Alcover_, Mar 01 2019 *)
%Y A024156 Cf. A024154, A024155.
%K A024156 nonn
%O A024156 1,13
%A A024156 _Clark Kimberling_