List_of_primes_faster.py

def primes(n): 
	if n==2: 
	    return [2]
	elif n<2: 
	    return []
	    
	s=range(3,n+1,2)
	
	mroot = n ** 0.5
	
	half=(n+1)/2-1
	i=0
	m=3
	while m <= mroot:
		if s[i]:
			j=(m*m-3)/2
			s[j]=0
			while j<half:
				s[j]=0
				j+=m
		i=i+1
		m=2*i+3
	return [2]+[x for x in s if x]

print primes(13)
print primes(30000)