'Return the lower central series for the group.
The lower central series for a group `G` is the series
`G = G_0 > G_1 > G_2 > \ldots` where
`G_k = [G, G_{k-1}]`, i.e. every term after the first is equal to the
commutator of `G` and the previous term in `G1` ([1], p.29).
Returns
A list of permutation groups in the order `G = G_0, G_1, G_2, \ldots`
Examples
>>> from sympy.combinatorics.named_groups import (AlternatingGroup,
... DihedralGroup)
>>> A = AlternatingGroup(4)
>>> len(A.lower_central_series())
2
>>> A.lower_central_series()[1].is_subgroup(DihedralGroup(2))
True
See Also
commutator, derived_series'

def lower_central_series(self):

    res = [self]
    current = self
    next = self.commutator(self, current)
    while (not current.is_subgroup(next)):
        res.append(next)
        current = next
        next = self.commutator(self, current)
    return res
