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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 24 |
| 5 | 76 |
| 6 | 313 |
| 7 | 1644 |
| 8 | 9397 |
| 9 | 56734 |
| 10 | 361386 |
| 11 | 2417777 |
| 12 | 16785520 |
| 13 | 120150723 |
| 14 | 882578840 |
[0,1,4,8,24,76,313,1644,9397,56734,361386,2417777, 16785520,120150723,882578840] |