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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 30 |
| 4 | 456 |
| 5 | 3396 |
| 6 | 14538 |
| 7 | 52840 |
| 8 | 150116 |
| 9 | 380336 |
| 10 | 860924 |
| 11 | 1839406 |
| 12 | 3551856 |
| 13 | 6684280 |
| 14 | 11834214 |
| 15 | 20108168 |
| 16 | 33051136 |
| 17 | 53176968 |
[0,0,0,30,456,3396,14538,52840,150116,380336, 860924,1839406,3551856,6684280,11834214,20108168, 33051136,53176968] |