Multiples of 3 and 5

--If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
--Find the sum of all the multiples of 3 or 5 below 1000.

--set up iterator
function list_iter()
    local i = 1;
    local n = 100;
    return function ()
        i = i + 1;
        if i < n then
            return i;
        end
    end
end

local sum = 0;
for i in list_iter() do
    if(i % 3 == 0 or i % 5 == 0) then
        print(i);
        sum = sum + i;
    end
end
print(sum);