What is this? Another version of the well known ...
def what(n):
x,y = range(n), [0]*n
x[1]= 0
z = 0
while z*z <= n:
z+=1
if x[z]: x[z*z:n:z]=y[z*z:n:z]
return [z for z in x if z]
Regards,
Gregor
(*) at least in good old Europe