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 A308426 #8 Jun 16 2020 14:34:53
%S A308426 0,0,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,4,4,4,0,8,12,8,9,12,8,9,0,8,17,
%T A308426 9,0,24,9,12,9,24,18,24,9,44,18,20,9,48,18,36,17,77,33,59,36,83,70,67,
%U A308426 65,123,88,63,81,111,92,89,74,169,75,90,66,154
%N A308426 Sum of the smallest side lengths of all integer-sided triangles with perimeter n whose sides are nonsquarefree.
%H A308426 Wikipedia, <a href="https://en.wikipedia.org/wiki/Integer_triangle">Integer Triangle</a>
%F A308426 a(n) = Sum_{k=1..floor(n/3)} Sum_{i=k..floor((n-k)/2)} sign(floor((i+k)/(n-i-k+1))) * (1 - mu(i)^2) * (1 - mu(k)^2) * (1 - mu(n-i-k)^2) * k, where mu is the Möbius function (A008683).
%t A308426 Table[Sum[Sum[k (1 - MoebiusMu[i]^2)*(1 - MoebiusMu[k]^2)*(1 - 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 A308426 Cf. A008683, A308424.
%K A308426 nonn
%O A308426 1,12
%A A308426 _Wesley Ivan Hurt_, May 26 2019