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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 78 |
| 4 | 546 |
| 5 | 3914 |
| 6 | 28554 |
| 7 | 211242 |
| 8 | 1577878 |
| 9 | 11867186 |
| 10 | 89815404 |
| 11 | 682642050 |
| 12 | 5211283212 |
| 13 | 39897460856 |
| 14 | 306446600454 |
| 15 | 2358644800468 |
| 16 | 18199380449274 |
| 17 | 140644480480176 |
| 18 | 1089068472750998 |
| 19 | 8443172123261506 |
| 20 | 65564035662489652 |
[1,12,78,546,3914,28554,211242,1577878,11867186, 89815404,682642050,5211283212,39897460856, 306446600454,2358644800468,18199380449274, 140644480480176,1089068472750998,8443172123261506, 65564035662489652] |