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 A070138 #24 Feb 16 2025 08:32:46 %S A070138 0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0, %T A070138 0,2,0,0,0,1,0,2,0,1,0,0,0,1,0,2,0,0,0,3,0,1,0,0,0,1,0,0,0,3,0,1,0,1, %U A070138 0,2,0,1,0,0,0,1,0,1,0,2,0,0,0,5,0,0,0,0,0,3 %N A070138 Number of integer triangles with an integer area having relatively prime sides a, b and c such that a + b + c = n. %C A070138 From _Peter Kagey_, Jan 30 2018: (Start) %C A070138 a(k) > 0 if and only if k is in A096468. %C A070138 Records appear at indices 12, 36, 54, 84, 98, 162, 242, 338, 484, 578, .... %C A070138 a(2k - 1) = 0 for all integers k > 0. %C A070138 (End) %H A070138 Peter Kagey, <a href="/A070138/b070138.txt">Table of n, a(n) for n = 1..10000</a> %H A070138 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HeronianTriangle.html">Heronian Triangle</a>. %H A070138 R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a> %Y A070138 Cf. A051493, A051516, A070088, A070109, A070143, A096468, A239246. %K A070138 nonn %O A070138 1,36 %A A070138 _Reinhard Zumkeller_, May 05 2002 %E A070138 Corrected by _T. D. Noe_, Jun 17 2004