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| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 6 |
| 7 | 6 |
| 8 | 32 |
| 9 | 72 |
| 10 | 120 |
| 11 | 316 |
| 12 | 804 |
| 13 | 1690 |
| 14 | 3896 |
| 15 | 10058 |
| 16 | 23656 |
| 17 | 54956 |
| 18 | 140334 |
| 19 | 351156 |
| 20 | 863336 |
| 21 | 2215008 |
| 22 | 5734726 |
| 23 | 14747386 |
| 24 | 38509606 |
| 25 | 101530298 |
| 26 | 267478776 |
| 27 | 707696286 |
| 28 | 1881659158 |
| 29 | 5006865152 |
| 30 | 13336830220 |
| 31 | 35597715792 |
[0,0,4,6,6,32,72,120,316,804,1690,3896,10058, 23656,54956,140334,351156,863336,2215008,5734726, 14747386,38509606,101530298,267478776,707696286, 1881659158,5006865152,13336830220,35597715792] |