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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 1 |
| 5 | 4 |
| 6 | 2 |
| 7 | 6 |
| 8 | 24 |
| 9 | 28 |
| 10 | 70 |
| 11 | 220 |
| 12 | 418 |
| 13 | 1079 |
| 14 | 3229 |
| 15 | 7816 |
| 16 | 20030 |
| 17 | 54017 |
| 18 | 137231 |
| 19 | 351289 |
| 20 | 913028 |
| 21 | 2360630 |
| 22 | 6135502 |
| 23 | 16039333 |
| 24 | 42102137 |
| 25 | 110891643 |
| 26 | 292830804 |
| 27 | 775990286 |
| 28 | 2060703746 |
| 29 | 5481264472 |
| 30 | 14616590748 |
| 31 | 39049205927 |
[0,1,4,2,6,24,28,70,220,418,1079,3229,7816,20030, 54017,137231,351289,913028,2360630,6135502, 16039333,42102137,110891643,292830804,775990286, 2060703746,5481264472,14616590748,39049205927] |