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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 17 |
| 6 | 45 |
| 7 | 273 |
| 8 | 2925 |
| 9 | 46625 |
| 10 | 908301 |
| 11 | 25944849 |
| 12 | 1141847565 |
| 13 | 74712257377 |
| 14 | 7074982666029 |
| 15 | 978286939049873 |
| 16 | 197925384324109741 |
| 17 | 58779837596021528865 |
[1,1,1,5,17,45,273,2925,46625,908301,25944849, 1141847565,74712257377,7074982666029, 978286939049873,197925384324109741, 58779837596021528865] |