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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 109 |
| 4 | 984 |
| 5 | 8857 |
| 6 | 79716 |
| 7 | 717445 |
| 8 | 6457008 |
| 9 | 58113073 |
| 10 | 523017660 |
| 11 | 4707158941 |
| 12 | 42364430472 |
| 13 | 381279874249 |
| 14 | 3431518868244 |
| 15 | 30883669814197 |
| 16 | 277953028327776 |
| 17 | 2501577254949985 |
| 18 | 22514195294549868 |
| 19 | 202627757650948813 |
| 20 | 1823649818858539320 |
| 21 | 16412848369726853881 |
[1,12,109,984,8857,79716,717445,6457008,58113073, 523017660,4707158941,42364430472,381279874249, 3431518868244,30883669814197,277953028327776, 2501577254949985,22514195294549868, 202627757650948813,1823649818858539320, 16412848369726853881] |