After looking at the prime number sieve code, and seeing how the concurrent structure works, I found it to be extremely elegant. However, it's also extremely inefficient, and IIRC, equivalent to the O(n^2) operation of testing the divisibility of the number m by dividing it by every number less than m. I figure that I could instead modify it to use the O(n^1.5) operation of checking the divisibility of m by dividing it by every number less than or equal to the sqrt(m). However, this turned out to be a lot harder than I anticipated.
I know this is more of an algorithmics question, but it's also one extremely relevant to concurrency. How would one implement the O(n^1.5) version of the algorithm?
One place to look is stackoverflow, for example, the question Concurrent Prime Generator. Amongst the answers is one that uses Go and channels.