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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 13 |
| 4 | 40 |
| 5 | 313 |
| 6 | 1833 |
| 7 | 27784 |
| 8 | 312227 |
| 9 | 9039597 |
| 10 | 194485968 |
| 11 | 10791499905 |
| 12 | 444739929613 |
| 13 | 47257907376576 |
| 14 | 3730171679762583 |
| 15 | 759195182636849001 |
| 16 | 114775951820515671520 |
| 17 | 44741688449064266073777 |
[1,2,3,13,40,313,1833,27784,312227,9039597, 194485968,10791499905,444739929613,47257907376576, 3730171679762583,759195182636849001, 114775951820515671520,44741688449064266073777] |