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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 21 |
| 4 | 243 |
| 5 | 3933 |
| 6 | 81819 |
| 7 | 2080053 |
| 8 | 62490339 |
| 9 | 2166106509 |
| 10 | 85092601707 |
| 11 | 3735939709989 |
| 12 | 181287330220467 |
| 13 | 9634718677393917 |
| 14 | 556569415611455931 |
| 15 | 34723276781195740437 |
| 16 | 2326773811332029313411 |
| 17 | 166666995789875216053101 |
| 18 | 12708546598923724476443403 |
[0,1,3,21,243,3933,81819,2080053,62490339, 2166106509,85092601707,3735939709989, 181287330220467,9634718677393917, 556569415611455931,34723276781195740437, 2326773811332029313411,166666995789875216053101, 12708546598923724476443403] |