def sieve(n) 
  eSieve = (2..n).to_a
  i = 0
  pbar = ProgressBar.new("sieving", n)
  while i < Math.sqrt(n)
    j = i + 1
    while (j < eSieve.length)
      if (eSieve[j] > (i ** 2)) and ((eSieve[j] % eSieve[i]) == 0)
        eSieve.delete_at j
        pbar.inc
      end
      j += 1
    end
    i += 1
    pbar.set(i + (n-eSieve.length))
  end
  pbar.finish
  eSieve
end

eSieve = sieve(600851475143)

def isPrime(n)
  eSieve.contains(n)
end

puts isPrime(7)

factors = []
for i in 1..600851475143
  if (600851475143 % i) == 0
    if isPrime(600851475143 % i)
      factors << i
    end
  end
end