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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 | 47 |
| 13 | 123 |
| 14 | 369 |
| 15 | 1165 |
| 16 | 4187 |
| 17 | 18445 |
| 18 | 79415 |
| 19 | 399577 |
| 20 | 2091817 |
| 21 | 12535539 |
| 22 | 80500731 |
[1,1,1,1,1,1,1,1,5,13,25,47,123,369,1165,4187, 18445,79415,399577,2091817,12535539,80500731] |