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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 0 |
| 5 | 1 |
| 6 | 8 |
| 7 | 18 |
| 8 | 12 |
| 9 | 0 |
| 10 | 0 |
| 11 | 1 |
| 12 | 26 |
| 13 | 306 |
| 14 | 1400 |
| 15 | 2800 |
| 16 | 2520 |
| 17 | 840 |
| 18 | 0 |
| 19 | 0 |
| 20 | 0 |
| 21 | 1 |
| 22 | 126 |
| 23 | 7971 |
| 24 | 153660 |
| 25 | 1268475 |
| 26 | 5463990 |
| 27 | 13534290 |
| 28 | 20018880 |
| 29 | 17478720 |
| 30 | 8316000 |
| 31 | 1663200 |
| 32 | 0 |
| 33 | 0 |
| 34 | 0 |
| 35 | 0 |
[1,1,2,0,1,8,18,12,0,0,1,26,306,1400,2800,2520, 840,0,0,0,1,126,7971,153660,1268475,5463990, 13534290,20018880,17478720,8316000,1663200,0,0,0, 0] |