Prime Sieve

Sieves are quick ways to yield primes, or other numbers, based on some rule of cancellation.

function sieve(N::Int)
	U = ones(N)
	U[1] = 0

	for p in 2:div(N,2)
		if U[p] == 1
			for m in 2*p:p:N
				U[m] = 0
			end
		end
	end

	U
end