A077438 Numbers n such that sum( d|n : mu(d)mu(n/d)^2) = -1.

4, 9, 25, 49, 121, 169, 289, 361, 529, 841, 900, 961, 1369, 1681, 1764, 1849, 2209, 2809, 3481, 3721, 4356, 4489, 4900, 5041, 5329, 6084, 6241, 6889, 7921, 9409, 10201, 10404, 10609, 11025, 11449, 11881, 12100, 12769, 12996, 16129, 16900