1 from math import sqrt
   2 
   3 N = int(raw_input("Inserire N: "))
   4 
   5 print 2
   6 primi = [2]
   7 for i in range(3,N,2):
   8     j = 0
   9     while primi[j] <= sqrt(i):
  10         if i%primi[j] == 0 : break
  11         j = j+1
  12     else:
  13         primi.append(i)
  14         print i

   1 def LuhnAlgorithm(aCreditCard):
   2     finalSum = 0
   3     index = 1
   4     for aNo in aCreditCard[::2]:
   5         aNo = int(aNo) * 2
   6         if aNo > 9: aNo -= 9
   7 
   8         finalSum += aNo + int(aCreditCard[index])
   9         index += 2
  10 
  11     return (finalSum % 10) == 0