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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 29 |
| 5 | 311 |
| 6 | 4447 |
| 7 | 79745 |
| 8 | 1722681 |
| 9 | 43578820 |
| 10 | 1264185051 |
| 11 | 41381702275 |
| 12 | 1509114454597 |
| 13 | 60681141052273 |
| 14 | 2667370764248023 |
| 15 | 127258109992533616 |
| 16 | 6549338612837162225 |
| 17 | 361680134713529977507 |
| 18 | 21333858798449021030515 |
| 19 | 1338681172839439064846881 |
[1,1,1,4,29,311,4447,79745,1722681,43578820, 1264185051,41381702275,1509114454597, 60681141052273,2667370764248023, 127258109992533616,6549338612837162225, 361680134713529977507,21333858798449021030515, 1338681172839439064846881] |