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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 5 |
| 10 | 13 |
| 11 | 25 |
| 12 | 45 |
| 13 | 129 |
| 14 | 391 |
| 15 | 1245 |
| 16 | 4737 |
| 17 | 21985 |
| 18 | 95961 |
| 19 | 496289 |
| 20 | 2673135 |
| 21 | 16997063 |
| 22 | 114065803 |
[1,1,1,1,1,1,1,1,5,13,25,45,129,391,1245,4737, 21985,95961,496289,2673135,16997063,114065803] |