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 A308116 #9 Jun 16 2020 13:09:51
%S A308116 0,0,3,0,5,6,14,8,9,0,22,12,39,28,75,48,51,36,38,20,63,66,138,96,75,
%T A308116 52,162,112,203,210,341,256,264,204,385,288,333,228,507,360,410,252,
%U A308116 559,396,720,552,940,720,833,600,765,520,848,756,825,616,684,580
%N A308116 Sum of the perimeters of the integer-sided triangles with perimeter n whose side lengths are squarefree.
%H A308116 Wikipedia, <a href="https://en.wikipedia.org/wiki/Integer_triangle">Integer Triangle</a>
%F A308116 a(n) = n * A308061(n).
%F A308116 a(n) = n * Sum_{k=1..floor(n/3)} Sum_{i=k..floor((n-k)/2)} sign(floor((i+k)/(n-i-k+1))) * mu(i)^2 * mu(k)^2 * mu(n-i-k)^2, where mu is the Möbius function (A008683).
%t A308116 Table[n*Sum[Sum[MoebiusMu[i]^2*MoebiusMu[k]^2*MoebiusMu[n - i - k]^2*Sign[Floor[(i + k)/(n - i - k + 1)]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}], {n, 100}]
%Y A308116 Cf. A008683, A308061.
%K A308116 nonn
%O A308116 1,3
%A A308116 _Wesley Ivan Hurt_, May 13 2019