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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 63 |
| 3 | 585 |
| 4 | 3951 |
| 5 | 38169 |
| 6 | 246303 |
| 7 | 2501865 |
| 8 | 15231951 |
| 9 | 164902329 |
| 10 | 931798143 |
| 11 | 10941169545 |
| 12 | 56148296751 |
| 13 | 731615910489 |
| 14 | 3311061455583 |
| 15 | 49365284099625 |
| 16 | 189031140702351 |
| 17 | 3365269314470649 |
| 18 | 10244972816098623 |
| 19 | 232054417825788105 |
[1,9,63,585,3951,38169,246303,2501865,15231951, 164902329,931798143,10941169545,56148296751, 731615910489,3311061455583,49365284099625, 189031140702351,3365269314470649, 10244972816098623,232054417825788105] |