mobius sieve/counting k free numbers

mobius sieve_counting k free numbers.py

def mobius_k_sieve(n, k):
    isprime = [1]*(n + 1)
    isprime[0] = isprime[1] = 0
    mob = [0] + [1]*(n)
    for p in range(2, n + 1):
        if isprime[p]:
            mob[p] *= -1
            for i in range(2*p, n + 1, p):
                isprime[i] = 0
                mob[i] *= -1
            sq = pow(p, k)
            if sq <= n:
                for j in range(sq, n + 1, sq):
                    mob[j] = 0
    return mob

def count_kfree(n, k):
    sq = int(pow(n, 1/k))
    mobius_k = mobius_k_sieve(sq, 2)
    return sum([mobius_k[i]*(n//pow(i, k)) for i in range(1, sq + 1)])