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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 126 |
| 3 | 1704 |
| 4 | 22986 |
| 5 | 310086 |
| 6 | 4183260 |
| 7 | 56435004 |
| 8 | 761346207 |
| 9 | 10271072557 |
| 10 | 138563678736 |
| 11 | 1869317246556 |
| 12 | 25218347263608 |
| 13 | 340212470558832 |
| 14 | 4589695110222504 |
| 15 | 61918074814238448 |
| 16 | 835316485437693186 |
| 17 | 11268981358631127288 |
| 18 | 152026139882340589466 |
[1,9,126,1704,22986,310086,4183260,56435004, 761346207,10271072557,138563678736,1869317246556, 25218347263608,340212470558832,4589695110222504, 61918074814238448,835316485437693186, 11268981358631127288,152026139882340589466] |