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 A070141 #7 Feb 16 2025 08:32:46 %S A070141 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0, %T A070141 0,2,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,3,0,0,0,0,0,1,0,0,0,3,0,1,0,0, %U A070141 0,0,0,3,0,0,0,1,0,1,0,2,0,0,0,4,0,0,0,1,0,2 %N A070141 Number of obtuse integer triangles with perimeter n having integral area. %C A070141 a(n) = A051516(n) - A070140(n) - A024155(n). %H A070141 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HeronianTriangle.html">Heronian Triangle</a>. %H A070141 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ObtuseTriangle.html">Obtuse Triangle</a>. %H A070141 R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a> %Y A070141 Cf. A051516, A070101, A070147. %K A070141 nonn %O A070141 1,36 %A A070141 _Reinhard Zumkeller_, May 05 2002