def get_atomic_numbers(mol, indices):
    """Get the atomic numbers for the specified atoms.

    Parameters
    ----------
    mol : rdkit.Chem.rdchem.Mol
        RDKit molecule instance.
    indices : list of int
        Specifying atoms.

    Returns
    -------
    list of int
        Atomic numbers computed.
    """
    atomic_numbers = []
    for i in indices:
        atom = mol.GetAtomWithIdx(i)
        atomic_numbers.append(atom.GetAtomicNum())
    return atomic_numbers
