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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 4 |
| 6 | 8 |
| 7 | 20 |
| 8 | 30 |
| 9 | 63 |
| 10 | 86 |
| 11 | 182 |
| 12 | 245 |
| 13 | 560 |
| 14 | 756 |
| 15 | 1784 |
| 16 | 2387 |
| 17 | 5600 |
| 18 | 7400 |
| 19 | 17336 |
| 20 | 22737 |
| 21 | 53850 |
| 22 | 70390 |
| 23 | 168610 |
| 24 | 219791 |
| 25 | 529529 |
| 26 | 688051 |
| 27 | 1662907 |
| 28 | 2154347 |
| 29 | 5225636 |
| 30 | 6754580 |
| 31 | 16451036 |
| 32 | 21225758 |
| 33 | 51878873 |
| 34 | 66826712 |
[0,0,0,1,4,8,20,30,63,86,182,245,560,756,1784, 2387,5600,7400,17336,22737,53850,70390,168610, 219791,529529,688051,1662907,2154347,5225636, 6754580,16451036,21225758,51878873,66826712] |