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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 15 |
| 4 | 20 |
| 5 | 15 |
| 6 | 6 |
| 7 | 1 |
| 8 | 1 |
| 9 | 12 |
| 10 | 66 |
| 11 | 220 |
| 12 | 495 |
| 13 | 792 |
| 14 | 924 |
| 15 | 792 |
| 16 | 495 |
| 17 | 220 |
| 18 | 66 |
| 19 | 12 |
| 20 | 1 |
| 21 | 1 |
| 22 | 18 |
| 23 | 153 |
| 24 | 816 |
| 25 | 3060 |
| 26 | 8568 |
| 27 | 18564 |
| 28 | 31824 |
| 29 | 43758 |
| 30 | 48620 |
| 31 | 43758 |
| 32 | 31824 |
| 33 | 18564 |
| 34 | 8568 |
| 35 | 3060 |
| 36 | 816 |
| 37 | 153 |
| 38 | 18 |
| 39 | 1 |
| 40 | 1 |
| 41 | 24 |
| 42 | 276 |
| 43 | 2024 |
| 44 | 10626 |
| 45 | 42504 |
| 46 | 134596 |
| 47 | 346104 |
| 48 | 735471 |
| 49 | 1307504 |
[1,1,6,15,20,15,6,1,1,12,66,220,495,792,924,792, 495,220,66,12,1,1,18,153,816,3060,8568,18564, 31824,43758,48620,43758,31824,18564,8568,3060,816, 153,18,1,1,24,276,2024,10626,42504,134596,346104, 735471,1307504] |