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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 18 |
| 5 | 56 |
| 6 | 60 |
| 7 | 88 |
| 8 | 1288 |
| 9 | 1784 |
| 10 | 3406 |
| 11 | 9250 |
| 12 | 11968 |
| 13 | 36216 |
| 14 | 57206 |
[1,2,4,18,56,60,88,1288,1784,3406,9250,11968, 36216,57206] |