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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 30 |
| 4 | 103 |
| 5 | 366 |
| 6 | 1323 |
| 7 | 4859 |
| 8 | 18033 |
| 9 | 67531 |
| 10 | 254620 |
| 11 | 965592 |
| 12 | 3679039 |
| 13 | 14074126 |
| 14 | 54023919 |
| 15 | 207985518 |
| 16 | 802774173 |
| 17 | 3105514305 |
| 18 | 12037590980 |
| 19 | 46743091795 |
| 20 | 181796906808 |
| 21 | 708073498446 |
| 22 | 2761428873186 |
| 23 | 10782065189898 |
| 24 | 42144216934185 |
[1,3,9,30,103,366,1323,4859,18033,67531,254620, 965592,3679039,14074126,54023919,207985518, 802774173,3105514305,12037590980,46743091795, 181796906808,708073498446,2761428873186, 10782065189898,42144216934185] |