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 = [ 0 ] * 100005 NEW_LINE def SieveOfEratosthenes ( n ) : NEW_LINE INDENT for i in range ( len ( prime ) ) : NEW_LINE INDENT prime [ i ] = True NEW_LINE DEDENT prime [ 1 ] = False NEW_LINE for p in range ( 2 , int ( sqrt ( n ) ) + 1 ) : NEW_LINE DEDENT