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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 21 |
| 3 | 105 |
| 4 | 325 |
| 5 | 780 |
| 6 | 1596 |
| 7 | 2926 |
| 8 | 4950 |
| 9 | 7875 |
| 10 | 11935 |
| 11 | 17391 |
| 12 | 24531 |
| 13 | 33670 |
| 14 | 45150 |
| 15 | 59340 |
| 16 | 76636 |
| 17 | 97461 |
| 18 | 122265 |
| 19 | 151525 |
| 20 | 185745 |
| 21 | 225456 |
| 22 | 271216 |
| 23 | 323610 |
| 24 | 383250 |
| 25 | 450775 |
| 26 | 526851 |
| 27 | 612171 |
| 28 | 707455 |
| 29 | 813450 |
| 30 | 930930 |
| 31 | 1060696 |
| 32 | 1203576 |
| 33 | 1360425 |
[0,1,21,105,325,780,1596,2926,4950,7875,11935, 17391,24531,33670,45150,59340,76636,97461,122265, 151525,185745,225456,271216,323610,383250,450775, 526851,612171,707455,813450,930930,1060696, 1203576,1360425] |