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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 414 |
| 3 | 2148 |
| 4 | 11064 |
| 5 | 57132 |
| 6 | 294648 |
| 7 | 1520856 |
| 8 | 7845624 |
| 9 | 40488216 |
| 10 | 208893336 |
| 11 | 1077925704 |
| 12 | 5561714424 |
| 13 | 28698381576 |
| 14 | 148076913912 |
| 15 | 764063601480 |
| 16 | 3942427621752 |
| 17 | 20342443076808 |
| 18 | 104963700280056 |
| 19 | 541598357861448 |
[81,414,2148,11064,57132,294648,1520856,7845624, 40488216,208893336,1077925704,5561714424, 28698381576,148076913912,764063601480, 3942427621752,20342443076808,104963700280056, 541598357861448] |