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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 57 |
| 3 | 369 |
| 4 | 2385 |
| 5 | 15417 |
| 6 | 99657 |
| 7 | 644193 |
| 8 | 4164129 |
| 9 | 26917353 |
| 10 | 173996505 |
| 11 | 1124731089 |
| 12 | 7270376049 |
| 13 | 46996449561 |
| 14 | 303789825513 |
| 15 | 1963728301761 |
| 16 | 12693739287105 |
| 17 | 82053620627913 |
| 18 | 530402941628793 |
| 19 | 3428578511656497 |
[1,9,57,369,2385,15417,99657,644193,4164129, 26917353,173996505,1124731089,7270376049, 46996449561,303789825513,1963728301761, 12693739287105,82053620627913,530402941628793, 3428578511656497] |