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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 111 |
| 5 | 571 |
| 6 | 3468 |
| 7 | 24340 |
| 8 | 194883 |
| 9 | 1754203 |
| 10 | 17542668 |
| 11 | 192970372 |
| 12 | 2315646974 |
| 13 | 30103414758 |
| 14 | 421447816520 |
| 15 | 6321717264184 |
| 16 | 101147476266147 |
| 17 | 1719507096590035 |
| 18 | 30951127738776012 |
| 19 | 588071427037006372 |
[1,2,7,25,111,571,3468,24340,194883,1754203, 17542668,192970372,2315646974,30103414758, 421447816520,6321717264184,101147476266147, 1719507096590035,30951127738776012, 588071427037006372] |