Define f on the integers n > 1 by the recurrence f(n) mAn{n, minm[ 2f(m) + 3f(n/m)}. The function f has f(n) n as its upper envelope, attained for all prime n. The goal of this paper is to determine the corresponding lower envelope. It is shown that this has the form f(n) C(logn)1+1/ for certain constants and C, in the sense that for any > 0, the inequality f(n) <_ (C+)(logn) 1+1/’ holds for in...