Prime number generator.

protos.py

# Author: Pedja 



print("                        ***** PROTOS *****\n\n\n")
while True:
	
    
   
    n=int(input("Enter the ordinal number : "))
	
    def lcm(p,q):
        p, q = abs(p), abs(q)
        m = p * q
        if not m: return 0
        while True:
            p %= q
            if not p: return m // q
            q %= p
            if not q: return m // p
    def nthprime(n):
        b1=2
        b2=2
        x=2
        k=3
        m=2
        while m<=n:
            b3=b1+lcm(k-1,b1)
            a=b3/b1-1
            k=k+1
            b1=b2
            b2=b3
            if x<a:
                x=a
                m=m+1
        return int(x)
	
	


   
    if n<1:
        print("Number must be greater than zero")
    elif n==1:
        print("The nth prime is 2")
    else:
        print("The nth prime is "+str(nthprime(n)))
    
		
    try_again = ""
    # Loop until users opts to go again or quit
    while not(try_again == "1") and not(try_again == "0"):
        try_again = input("Press 1 to try again, 0 to exit. ")
        if try_again in ["1", "0"]:
            continue  # a valid entry found
        else:
            print("Invalid input- Press 1 to try again, 0 to exit.") 
    # at this point, try_again must be "0" or "1"
    if try_again == "0":
        break