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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 21 |
| 5 | 37 |
| 6 | 39 |
| 7 | 91 |
| 8 | 1443 |
| 9 | 3367 |
| 10 | 9901 |
| 11 | 157737 |
| 12 | 333667 |
| 13 | 999001 |
| 14 | 3075403 |
| 15 | 9226209 |
| 16 | 14287143 |
| 17 | 33336667 |
| 18 | 99990001 |
| 19 | 1171182883 |
| 20 | 1224848037 |
| 21 | 1286294191 |
| 22 | 1397863441 |
| 23 | 1428557143 |
| 24 | 1469179621 |
| 25 | 1535254357 |
| 26 | 1568996211 |
| 27 | 1753536967 |
| 28 | 1792076241 |
| 29 | 1839599913 |
| 30 | 1891910811 |
[1,3,13,21,37,39,91,1443,3367,9901,157737,333667, 999001,3075403,9226209,14287143,33336667,99990001, 1171182883,1224848037,1286294191,1397863441, 1428557143,1469179621,1535254357,1568996211, 1753536967,1792076241,1839599913,1891910811] |