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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 6 |
| 3 | 20 |
| 4 | 56 |
| 5 | 120 |
| 6 | 792 |
| 7 | 364 |
| 8 | 560 |
| 9 | 8568 |
| 10 | 1140 |
| 11 | 1540 |
| 12 | 42504 |
| 13 | 2600 |
| 14 | 98280 |
| 15 | 2035800 |
| 16 | 4960 |
| 17 | 5984 |
| 18 | 376992 |
| 19 | 12620256 |
| 20 | 9880 |
| 21 | 850668 |
| 22 | 13244 |
| 23 | 15180 |
| 24 | 1712304 |
| 25 | 19600 |
| 26 | 2598960 |
| 27 | 177100560 |
| 28 | 27720 |
| 29 | 4582116 |
| 30 | 386206920 |
| 31 | 37820 |
| 32 | 41664 |
| 33 | 8936928 |
| 34 | 969443904 |
| 35 | 54740 |
| 36 | 13991544 |
[0,2,6,20,56,120,792,364,560,8568,1140,1540,42504, 2600,98280,2035800,4960,5984,376992,12620256,9880, 850668,13244,15180,1712304,19600,2598960, 177100560,27720,4582116,386206920,37820,41664, 8936928,969443904,54740,13991544] |