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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 28 |
| 5 | 89 |
| 6 | 286 |
| 7 | 924 |
| 8 | 2993 |
| 9 | 9707 |
| 10 | 31501 |
| 11 | 102256 |
| 12 | 331981 |
| 13 | 1077870 |
| 14 | 3499720 |
| 15 | 11363361 |
| 16 | 36896355 |
| 17 | 119801329 |
| 18 | 388991876 |
| 19 | 1263047761 |
| 20 | 4101088878 |
| 21 | 13316149700 |
| 22 | 43237262993 |
| 23 | 140390505643 |
| 24 | 455845099957 |
| 25 | 1480119728920 |
[1,3,9,28,89,286,924,2993,9707,31501,102256, 331981,1077870,3499720,11363361,36896355, 119801329,388991876,1263047761,4101088878, 13316149700,43237262993,140390505643,455845099957, 1480119728920] |