function getPrimes(range)
    local primes    = {}
    local range     = range or 2

    for number = 2, range do
        local isPrime = true
        for _, prime in pairs(primes) do
            if number % prime == 0 then
                isPrime = false
                break
            end
        end
        if isPrime then
            table.insert(primes, number)
        end
    end

    return primes
end