First numbers that belong to both sets:
12,
54,
56,
78,
234,
654,
678,
5456,
21234,
23212,
65454,
67676,
89898,
567678,
765654,
2343234,
4345456,
6545454,
6767898,
8987898,
12345654,
34543434,
54323454,
54543234,
56765454,
76545654,
98765454.