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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 72 |
| 3 | 576 |
| 4 | 4608 |
| 5 | 36864 |
| 6 | 294876 |
| 7 | 2358720 |
| 8 | 18867492 |
| 9 | 150921792 |
| 10 | 1207229184 |
| 11 | 9656672256 |
| 12 | 77244089580 |
| 13 | 617878417968 |
| 14 | 4942433025684 |
| 15 | 39534710232528 |
| 16 | 316239654648960 |
| 17 | 2529613056079872 |
| 18 | 20234471292326844 |
| 19 | 161856307428494112 |
[1,9,72,576,4608,36864,294876,2358720,18867492, 150921792,1207229184,9656672256,77244089580, 617878417968,4942433025684,39534710232528, 316239654648960,2529613056079872, 20234471292326844,161856307428494112] |