Abstract :
We give asymptotic estimates for the sums ∑nless-than-or-equals, slantx, p(n)less-than-or-equals, slanty d(d(n)) and ∑nless-than-or-equals, slantx d(d(n))/p(n), whered(n) is the divisor function andp(n) denotes the largest prime factor ofn.