First numbers that belong to both sets:
6,
12,
18,
24,
28,
36,
48,
56,
66,
78,
88,
112,
114,
126,
138,
144,
156,
168,
222,
224,
228,
234,
246,
258,
288,
336,
348,
366,
368,
378,
444,
448,
456,
468,
558,
588,
666,
678,
888,
1116,
1122,
1128,
1134,
1144,
1146,
1148,
1158,
1188,
1224,
1236,
1248,
1266,
1278,
1288,
1338,
1344,
1356,
1368,
1446,
1456,
1458,
1488,
1566,
1568,
1578,
1668,
1788,
1888,
2226,
2238,
2244,
2256,
2268,
2288,
2334,
2346,
2358,
2368,
2388,
2448,
2466,
2478,
2556,
2568,
2688,
2778,
3336,
3344,
3348,
3366,
3378,
3388,
3444,
3456,
3468,
3556,
3558,
3588,
3666,
3668,
3678,
3888,
4446,
4458,
4488,
4566,
4578,
4668,
4788,
4888,
5556,
5568,
5688,
5778,
5888,
6666,
6678,
6688,
6888,
7788,
7888,
8888,
11112,
11116,
11118,
11124,
11128,
11136,
11144,
11148,
11166,
11178,
11226,
11228,
11238,
11244,
11248,
11256,
11268,
11288,
11334,
11336,
11346,
11358,
11368,
11388,
11448,
11466,
11478,
11556,
11568,
11688,
11778,
11788,
12222,
12228,
12234,
12236,
12246,
12258,
12288,
12336,
12348,
12366,
12378,
12444,
12456,
12468,
12488,
12558,
12588,
12666,
12678,
12688,
12888,
13338,
13344,
13356,
13368,
13446,
13456,
13458,
13468,
13488,
13566,
13568,
13578,
13668,
13788,
13888,
14448,
14456,
14466,
14478,
14556,
14568,
14588,
14688,
14778,
15558,
15568,
15588,
15666,
15678,
15888,
16668,
16688,
16788,
17778,
17888,
18888,
22224,
22236,
22248,
22256,
22266,
22278,
22288,
22338,
22344,
22356,
22368,
22446,
22448,
22456,
22458,
22488,
22566,
22568,
22578,
22668,
22788,
23334,
23346,
23358,
23388,
23448,
23466,
23478,
23556,
23568,
23688,
23778,
24444,
24448,
24456,
24468,
24556,
24558,
24588,
24666,
24668,
24678,
24888,
25566,
25568,
25578,
25668,
25688,
25788,
26688,
26778,
27888,
33336,
33345,
33348,
33366,
33378,
33444,
33456,
33468,
33488,
33558,
33588,
33666,
33678,
33888,
34446,
34458,
34468.
Some larger examples :
566778,
566888,
567888,
568888,
577788,
588888,
666666,
666678,
666688,
666888,
667788,
667888,
668888,
677778,
677888,
678888,
777888,
778888,
888888,
999999.