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 A024155 #16 Feb 16 2025 08:32:34 %S A024155 0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0, %T A024155 0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,2,0,0,0,0,0,0,0,0, %U A024155 0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,2,0,0,0,0,0,2,0,0,0,0,0,1,0,0,0,0 %N A024155 Number of integer-sided triangles with sides a,b,c, a<b<c, a+b+c=n that are right triangles. %C A024155 Also number of right integer triangles with perimeter n having integral inradius. - _Reinhard Zumkeller_, May 05 2002 %C A024155 Every integer-sided right triangle has integer inradius. If the triple is [p^2-q^2,2pq,p^2+q^2] then inradius = pq-q^2. - _Michael Somos_, Sep 13 2005 %H A024155 Seiichi Manyama, <a href="/A024155/b024155.txt">Table of n, a(n) for n = 1..1000</a> %H A024155 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Incircle.html">Incircle</a>. %H A024155 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RightTriangle.html">Right Triangle</a>. %H A024155 R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a> %F A024155 a(n) = A070201(n) - A070205(n) - A070206(n). %Y A024155 Cf. A005044, A070093, A070101. %K A024155 nonn %O A024155 1,60 %A A024155 _Clark Kimberling_