def A000041(n: int) -> int:
    """Parittion numbers.

    a(n) is the number of partitions of n (the partition numbers).
    """
    parts = [0] * (n + 1)
    parts[0] = 1
    for value in range(1, n + 1):
        for j in range(value, n + 1):
            parts[j] += parts[j - value]
    return parts[n]