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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 1 |
| 4 | 3 |
| 5 | 9 |
| 6 | 19 |
| 7 | 31 |
| 8 | 199 |
| 9 | 330 |
| 10 | 1377 |
| 11 | 6627 |
| 12 | 23223 |
| 13 | 113179 |
| 14 | 849856 |
| 15 | 5207476 |
| 16 | 43357615 |
[0,4,1,3,9,19,31,199,330,1377,6627,23223,113179, 849856,5207476,43357615] |