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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 31 |
| 4 | 359 |
| 5 | 5546 |
| 6 | 107249 |
| 7 | 2492701 |
| 8 | 67693534 |
| 9 | 2103854581 |
| 10 | 73651161959 |
| 11 | 2868077514776 |
| 12 | 122980857764819 |
| 13 | 5758029769553101 |
| 14 | 292305762924889804 |
| 15 | 15992593021331060611 |
| 16 | 938143525674896325299 |
| 17 | 58739433900424758545186 |
| 18 | 3910020681156059085488189 |
[1,4,31,359,5546,107249,2492701,67693534, 2103854581,73651161959,2868077514776, 122980857764819,5758029769553101, 292305762924889804,15992593021331060611, 938143525674896325299,58739433900424758545186, 3910020681156059085488189] |