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 A070200 #11 Feb 16 2025 08:32:46 %S A070200 0,0,1,0,1,1,0,1,1,1,1,0,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1, %T A070200 1,1,1,1,2,0,1,1,1,1,1,1,2,1,1,1,1,1,2,2,0,1,1,1,1,1,1,2,2,2,1,1,1,2, %U A070200 1,2,2,2,0,1,1,1,1,2,1,2,2,2,2,2,1,1,1,2,1,2 %N A070200 Inradii of integer triangles [A070080(n), A070081(n), A070082(n)], rounded values. %C A070200 Triangles [A070080(A070209(n)), A070081(A070209(n)), A070082(A070209(n))] have integer inradii = a(A070209(k))= A070210(k). %H A070200 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Incircle.html">Incircle</a>. %H A070200 R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a> %F A070200 a(n) = sqrt((s-u)*(s-v)*(s-w)/s), where u=A070080(n), v=A070081(n), w=A070082(n) and s=A070083(n)/2=(u+v+w)/2. %e A070200 [A070080(25), A070081(25), A070082(25)] = [3,5,6] and s = A070083(25)/2 = (3+5+6)/2 = 7: a(25) = sqrt((s-3)*(s-5)*(s-6)/7) = sqrt((7-3)*(7-5)*(7-6)/7) = sqrt(4*2*1/7) = sqrt(8/7) = 1.069, rounded = 1. %Y A070200 Cf. A070086. %K A070200 nonn %O A070200 1,39 %A A070200 _Reinhard Zumkeller_, May 05 2002