Code optimization

[Thisisnotanid]

Hi all, I wrote code to list primes that are in a given "radius" of an even number. For example, 6 - 1 = 5 and 6 + 1 = 7, 14 - 3 = 11 and 14 + 3 = 17, etc. I used Euler's sieve to obtain the primes. Can the following code be further optimized? If so, how? I eventually want to be able to plot the primes for a given even number. All help is appreciated, thanks!

Here's the code:

n = int(raw_input("Num: ")) 

s = range(3, n+1, 2) 

i = 1 

a = len(s) - 1

for l in xrange(0, a + 1): 
	a1 = i
	j = (l + (s[l]*i))
	while (j <= a) and s[l] != 0: 
		s[j] = 0
		i += 1 
		j = (l + (s[l]*i)) 
	i = a1 + 1

s = list(set(s))
s.sort()
s.remove(0)

# All the code above this point is an implementation of Euler's sieve.


a = s[-1] - 1

pR = []
pRc = []


for i in xrange(4, a + 1, 2):
	for l in xrange(1, i - 2, 2):
		c = i + l
		d = i - l	
		if c in s and d in s:
			pR.append(c)
			pR.append(d)
	for k in pR:
		pRc.append(k)
	pRc.append(str(i))
	pR = []

print pRc