# Listing subgroups of given index

I need to consider subgroups of a given index to a group. So far I used the `.conjugacy_classes_subgroups()` method but this takes too much time (and memory), since it computes all subgroups. For example I used:

G = PrimitiveGroup(81,146); ConjClassList = G..conjugacy_classes_subgroups()

then the computer runs out of memory. But there might be only a few subgroups with a given index. Is there a relatviely efficient way to do so?