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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 48 |
| 8 | 115 |
| 9 | 286 |
| 10 | 719 |
| 11 | 1841 |
| 12 | 4762 |
| 13 | 12470 |
| 14 | 32918 |
| 15 | 87628 |
| 16 | 234795 |
| 17 | 633000 |
| 18 | 1715435 |
| 19 | 4671098 |
| 20 | 12772707 |
| 21 | 35059815 |
| 22 | 96567161 |
| 23 | 266818396 |
| 24 | 739344427 |
[1,1,2,4,9,20,48,115,286,719,1841,4762,12470, 32918,87628,234795,633000,1715435,4671098, 12772707,35059815,96567161,266818396,739344427] |