Create sieveOfEratosthenes.py

The sieve of Eratosthenes is one of the most efficient ways to find all primes smaller than n when n is smaller than 10 million or so

Python/sieveOfEratosthenes.py

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+# Python program to print all primes smaller than or equal to 
+# n using Sieve of Eratosthenes 
+
+def SieveOfEratosthenes(n): 
+
+	# Create a boolean array "prime[0..n]" and initialize 
+	# all entries it as true. A value in prime[i] will 
+	# finally be false if i is Not a prime, else true. 
+	prime = [True for i in range(n+1)] 
+	p = 2
+	while (p * p <= n): 
+
+		# If prime[p] is not changed, then it is a prime 
+		if (prime[p] == True): 
+
+			# Update all multiples of p 
+			for i in range(p * p, n+1, p): 
+				prime[i] = False
+		p += 1
+
+	# Print all prime numbers 
+	for p in range(2, n): 
+		if prime[p]: 
+			print p, 
+
+# driver program 
+if __name__=='__main__': 
+	n = 30
+	print "Following are the prime numbers smaller", 
+	print "than or equal to", n 
+	SieveOfEratosthenes(n)