A063038 Floor(n*sqrt(n))- d(n), where d(n) is the number of divisors function.

0, 0, 3, 5, 9, 10, 16, 18, 24, 27, 34, 35, 44, 48, 54, 59, 68, 70, 80, 83, 92, 99, 108, 109, 122, 128, 136, 142, 154, 156, 170, 175, 185, 194, 203, 207, 223, 230, 239, 244, 260, 264, 279, 285, 295, 307, 320, 322, 340, 347, 360, 368, 383, 388, 403, 411, 426, 437