20F22 9 20E34 5 20F19 5 20E15 4 20F50 4 abnormal subgroups 4 pronormal subgroups 4 locally nilpotent radical 3 soluble group 3 20F16 2 20F18 2 20H20 2 arrangement of subgroups 2 fan subgroups 2 finite special rank 2 locally finite group 2 locally graded group 2 locally nilpotent residual 2 normal subgroup 2 normal subgroups 2 periodic group 2 self-normalizing subgroup 2 subnormal subgroup 2 transitively normal subgroups 2 (generalized) radical group 1 20-00 1 20B07 1 20C07 1 20E07 1 20E15,20E34,20F19,20F22 1