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 A366563 #10 Oct 14 2023 14:07:20
%S A366563 1,2,2,2,2,4,2,3,3,4,2,4,2,4,4,4,2,6,2,4,4,4,2,6,3,4,4,4,2,8,2,5,4,4,
%T A366563 4,6,2,4,4,6,2,8,2,4,6,4,2,8,3,6,4,4,2,8,4,6,4,4,2,8,2,4,6,6,4,8,2,4,
%U A366563 4,8,2,9,2,4
%N A366563 Number of nonzero terms in row n of A366561(n,k).
%F A366563 a(n) = Sum_{k=1..n} abs(sign(A366561(n,k))).
%t A366563 nn = 74; f = x^2 - y^2; g[n_] := DivisorSum[n, MoebiusMu[#] # &]; Table[Sum[Abs[Sign[Sum[Sum[If[GCD[f, n] == k, 1, 0], {x, 1, n}], {y, 1, n}]]], {k, 1, n}], {n, 1, nn}]
%Y A366563 Cf. A366561, A366562, A000005, A320111.
%K A366563 nonn
%O A366563 1,2
%A A366563 _Mats Granvik_, Oct 13 2023