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A366563
Number of nonzero terms in row n of A366561(n,k).
2
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, 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, 4, 8, 2, 9, 2, 4
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