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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 97 |
| 3 | 660 |
| 4 | 4081 |
| 5 | 23772 |
| 6 | 133057 |
| 7 | 724260 |
| 8 | 3863761 |
| 9 | 20308332 |
| 10 | 105558817 |
| 11 | 544039860 |
| 12 | 2785713841 |
| 13 | 14192221692 |
| 14 | 72020501377 |
| 15 | 364354427460 |
| 16 | 1838822866321 |
| 17 | 9262446387852 |
| 18 | 46585947584737 |
[1,12,97,660,4081,23772,133057,724260,3863761, 20308332,105558817,544039860,2785713841, 14192221692,72020501377,364354427460, 1838822866321,9262446387852,46585947584737] |