First numbers that belong to both sets:
1,
4,
9,
121,
484,
676,
10201,
12321,
14641,
40804,
44944,
69696,
94249,
698896,
1002001,
1234321,
4008004,
5221225,
6948496,
100020001,
102030201,
104060401,
121242121,
123454321,
125686521,
400080004,
404090404,
522808225,
617323716,
942060249,
10000200001,
10221412201,
12102420121,
12345654321,
40000800004,
637832238736,
1000002000001,
1002003002001,
1004006004001,
1020304030201,
1022325232201,
1024348434201,
1086078706801,
1210024200121,
1212225222121,
1214428244121,
1230127210321,
1232346432321,
1234567654321,
1615108015161,
4000008000004,
4004009004004,
4051154511504,
5265533355625,
9420645460249,
100000020000001,
100220141022001,
102012040210201,
102234363432201,
121000242000121,
121242363242121,
123212464212321,
123456787654321,
123862676268321,
144678292876441,
165551171155561,
400000080000004,
900075181570009.