Removal of Multiples

# Removal of Multiples drill from Programming Praxis

function main(s::Array{Int64, 1}, N::Int64)
    ind = trues(N)

    for x in s # iterate over all elements of s
        if ind[x] # x isn't a multiple of the previous elements of s
            for i = x:x:N
                ind[i] = false
            end
        end
    end

    return (1:N)[ind]
end