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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 5 |
| 7 | 15 |
| 8 | 30 |
| 9 | 70 |
| 10 | 105 |
| 11 | 213 |
| 12 | 286 |
| 13 | 558 |
| 14 | 720 |
| 15 | 1500 |
| 16 | 1935 |
| 17 | 4455 |
| 18 | 5775 |
| 19 | 13895 |
| 20 | 17876 |
| 21 | 42484 |
| 22 | 53859 |
| 23 | 124761 |
| 24 | 156065 |
| 25 | 357825 |
| 26 | 444015 |
| 27 | 1028500 |
| 28 | 1272155 |
| 29 | 3002795 |
| 30 | 3709043 |
| 31 | 8871603 |
| 32 | 10935267 |
| 33 | 26243427 |
[0,0,0,0,0,5,15,30,70,105,213,286,558,720,1500, 1935,4455,5775,13895,17876,42484,53859,124761, 156065,357825,444015,1028500,1272155,3002795, 3709043,8871603,10935267,26243427] |