OFFSET
1,2
COMMENTS
MATHEMATICA
nn = 84; f = x^3 - x^2 - y^2 - y; g[n_] := DivisorSum[n, MoebiusMu[#] # &]; Monitor[Table[Sum[Sum[Sum[If[GCD[f, n] == k, 1, 0]*g[k]/n, {x, 1, n}], {y, 1, n}], {k, 1, n}], {n, 1, nn}], n]
PROG
(PARI) a(n) = sum(k=1, n, my(z=sumdivmult(k, d, d*moebius(d))); sum(y=1, n, sum(x=1, n, if (gcd(x^3 - x^2 - y^2 - y, n)==k, z/n)))); \\ Michel Marcus, Oct 10 2023
CROSSREFS
KEYWORD
sign
AUTHOR
Mats Granvik, Oct 10 2023
STATUS
approved