Just wanted to post some data about sum-free sets.

First is a triangle table of membership counts. Each row corresponds to sum-free subsets of {1, ..., n}; each column k is the number of times k is a member of any of these subsets.

Data here. Row sums here.

And a graph showing membership counts through n=49. The program I posted the other day starts with the largest numbers (highest bit), and works down. This graph shows this will iterate over many more choices than by starting with smaller numbers. I'd have to make some substantial chnages to the program to make use of this information though...