Euler #87

def primes_sieve(limit):
    a = [True] * limit
    a[0] = a[1] = False

    for (i, isprime) in enumerate(a):
        if isprime:
            yield i
            for n in range(i * i, limit, i):
                a[n] = False

primes, nums = list(primes_sieve(7072)), []

for a in primes:
    print(primes.index(a))
    for b in primes:
        for c in primes:
            if (a**2 + b**3 + c**4) < 50*(10**6):
                nums.append(a**2 + b**3 + c**4)
                continue
            break
print(len(set(nums)))