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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 36 |
| 7 | 121 |
| 8 | 505 |
| 9 | 2613 |
| 10 | 17219 |
| 11 | 144696 |
| 12 | 1542668 |
| 13 | 20695228 |
| 14 | 347085846 |
[0,1,2,5,12,36,121,505,2613,17219,144696,1542668, 20695228,347085846] |