An addition chain for a positive integer n is a set t = uoc: a, < . . . c a, = n of integers such that fw each i 3 1. a, = a, + ak for scjrne k c j < i. The smallest length I for which an addition cham for n exists is denoted by I(n). This paper introduces the function h(x) which denotes the number of Integers n less than or equal to x for which l(b) = l(n… (More)