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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 1 |
| 9 | 80 |
| 10 | 1944 |
| 11 | 25200 |
| 12 | 217800 |
| 13 | 1411344 |
| 14 | 7361640 |
| 15 | 32391216 |
| 16 | 124227675 |
| 17 | 425339200 |
| 18 | 1323786464 |
| 19 | 3797876160 |
| 20 | 10155802176 |
| 21 | 25539739200 |
| 22 | 60844672800 |
| 23 | 138154965696 |
| 24 | 300509773245 |
| 25 | 628886888784 |
| 26 | 1270898695000 |
| 27 | 2488029830000 |
| 28 | 4731583685400 |
| 29 | 8762192010000 |
[0,0,0,0,0,0,0,1,80,1944,25200,217800,1411344, 7361640,32391216,124227675,425339200,1323786464, 3797876160,10155802176,25539739200,60844672800, 138154965696,300509773245,628886888784, 1270898695000,2488029830000,4731583685400, 8762192010000] |