Ex Machina Easter egg - Book recommendation

bluebook_code_decryption.py

# BlueBook code decryption

import sys

def sieve(n):
# Compute primes using sieve of Eratosthenes

    x = [1]*n
    x[1] = 0

    for i in range(2, n/2):
        j = 2*i
        while j < n:
            x[j] = 0
            j = j+i

    return x

def prime(n, x):
# Find nth prime

    i = 1
    j = 1
    while j <= n:
        if x[i] == 1:
            j = j+1
        i = i+1
    return i-1

# Compute BlueBook unlock code

x = sieve(10000)

code = [1206,301,384,5]
key = [1,1,2,2]

sys.stdout.write("".join(chr(i) for i in [73,83,66,78,32,61,32]))

for i in range(0, 4):
    sys.stdout.write(str(prime(code[i],x)-key[i]))
print

The result is ISBN = 9780199226559

Here the amazon link: https://www.amazon.com/Embodiment-inner-life-Cognition-Consciousness/dp/0199226555/