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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 18 |
| 3 | 254 |
| 4 | 2684 |
| 5 | 26157 |
| 6 | 246237 |
| 7 | 2241332 |
| 8 | 19885341 |
| 9 | 172968364 |
| 10 | 1481176019 |
| 11 | 12518566165 |
| 12 | 104634697841 |
| 13 | 866300549164 |
| 14 | 7113499311107 |
| 15 | 57991161908834 |
| 16 | 469750378139503 |
| 17 | 3783568376847729 |
| 18 | 30319325084628268 |
| 19 | 241845032680119474 |
[3,18,254,2684,26157,246237,2241332,19885341, 172968364,1481176019,12518566165,104634697841, 866300549164,7113499311107,57991161908834, 469750378139503,3783568376847729, 30319325084628268,241845032680119474] |