def prime_sieve(num: int) -> list[int]:

    if num <= 0:
        raise ValueError(f"{num}: Invalid input, please enter a positive integer.")

    sieve = [True] * (num + 1)
    prime = []
    start = 2
    end = int(math.sqrt(num))

    while start <= end:
        # If start is a prime
        if sieve[start] is True:
            prime.append(start)

            # Set multiples of start be False
            for i in range(start * start, num + 1, start):
                if sieve[i] is True:
                    sieve[i] = False

        start += 1

    for j in range(end + 1, num + 1):
        if sieve[j] is True:
            prime.append(j)

    return prime