“…respectively, where a = 0 is a fixed parameter, and c > 0 is a constant, as x → ∞, confer [15], [22], [25], [23], [13], et alii. Another attempt to prove the arithmetic average order of (1) was made in [12], and an improved error term O(( √ log log x) −2 ) was just proposed in [8, Corollary 2]. Observe that a stronger error term, approximately O((log x) −2 ), is required to compute the arithmetic average orders directly from (1), and (2), see [7,Exercise 2.12] for explanation.…”