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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 64 |
| 4 | 381 |
| 5 | 2430 |
| 6 | 16227 |
| 7 | 112008 |
| 8 | 792717 |
| 9 | 5721165 |
| 10 | 41945373 |
| 11 | 311529831 |
| 12 | 2338909219 |
| 13 | 17722127580 |
| 14 | 135346614906 |
| 15 | 1040779011412 |
| 16 | 8051611785006 |
| 17 | 62620659604659 |
| 18 | 489339248275242 |
| 19 | 3840135625895886 |
| 20 | 30251386980891657 |
| 21 | 239138782521553659 |
| 22 | 1896380840948325606 |
[1,3,12,64,381,2430,16227,112008,792717,5721165, 41945373,311529831,2338909219,17722127580, 135346614906,1040779011412,8051611785006, 62620659604659,489339248275242,3840135625895886, 30251386980891657,239138782521553659, 1896380840948325606] |