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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 144 |
| 5 | 441 |
| 6 | 10404 |
| 7 | 12321 |
| 8 | 40401 |
| 9 | 69696 |
| 10 | 1004004 |
| 11 | 1022121 |
| 12 | 1212201 |
| 13 | 4004001 |
| 14 | 4088484 |
| 15 | 4848804 |
| 16 | 100040004 |
| 17 | 100220121 |
| 18 | 102030201 |
| 19 | 121022001 |
| 20 | 400040001 |
| 21 | 400880484 |
| 22 | 404492544 |
| 23 | 420578064 |
| 24 | 445294404 |
| 25 | 460875024 |
| 26 | 484088004 |
| 27 | 617323716 |
| 28 | 10000400004 |
| 29 | 10002200121 |
[1,4,9,144,441,10404,12321,40401,69696,1004004, 1022121,1212201,4004001,4088484,4848804,100040004, 100220121,102030201,121022001,400040001,400880484, 404492544,420578064,445294404,460875024,484088004, 617323716,10000400004,10002200121] |