OFFSET
1,2
FORMULA
a(n) = Sum_{k=1..n} abs(sign(A366561(n,k))).
MATHEMATICA
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}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Mats Granvik, Oct 13 2023
STATUS
approved