Number of terms in S000461(n) that are zero.
1, 1, 2, 2, 4, 6, 9, 16, 12, 26, 37, 91, 94, 148, 181, 150, 276, 801, 631, 1720
1
T. D. Noe, Plot of 20 terms
(Mma) Table[Count[Table[Total[DivisorSigma[0, s]]^2 - Total[DivisorSigma[0, s]^3], {s, Complement[Subsets[Range[n]], Subsets[Range[n - 1]]]}], 0], {n, 20}]
Cf. S000461.
nonn
T. D. Noe, Feb 02 2015