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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 95 |
| 5 | 390 |
| 6 | 1620 |
| 7 | 6965 |
| 8 | 30522 |
| 9 | 135385 |
| 10 | 610014 |
| 11 | 2771126 |
| 12 | 12705652 |
| 13 | 58683457 |
| 14 | 272604795 |
| 15 | 1273727257 |
| 16 | 5977473827 |
| 17 | 28170926189 |
| 18 | 133252922101 |
| 19 | 632302591304 |
| 20 | 3009403153390 |
| 21 | 14359827264254 |
| 22 | 68684367797437 |
| 23 | 329238009252576 |
| 24 | 1581273797990676 |
| 25 | 7608459327441592 |
| 26 | 36669229629765119 |
| 27 | 176998764917494340 |
[1,2,7,25,95,390,1620,6965,30522,135385,610014, 2771126,12705652,58683457,272604795,1273727257, 5977473827,28170926189,133252922101,632302591304, 3009403153390,14359827264254,68684367797437, 329238009252576,1581273797990676,7608459327441592, 36669229629765119,176998764917494340] |