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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 26 |
| 4 | 73 |
| 5 | 199 |
| 6 | 542 |
| 7 | 1475 |
| 8 | 4011 |
| 9 | 10903 |
| 10 | 29640 |
| 11 | 80571 |
| 12 | 219017 |
| 13 | 595350 |
| 14 | 1618331 |
| 15 | 4399082 |
| 16 | 11957946 |
| 17 | 32505069 |
| 18 | 88357939 |
| 19 | 240181783 |
| 20 | 652881776 |
| 21 | 1774716669 |
| 22 | 4824180073 |
| 23 | 13113481032 |
| 24 | 35646137200 |
| 25 | 96896247006 |
| 26 | 263391307484 |
[1,3,9,26,73,199,542,1475,4011,10903,29640,80571, 219017,595350,1618331,4399082,11957946,32505069, 88357939,240181783,652881776,1774716669, 4824180073,13113481032,35646137200,96896247006, 263391307484] |