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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 45 |
| 4 | 585 |
| 5 | 9945 |
| 6 | 208845 |
| 7 | 5221125 |
| 8 | 151412625 |
| 9 | 4996616625 |
| 10 | 184874815125 |
| 11 | 7579867420125 |
| 12 | 341094033905625 |
| 13 | 16713607661375625 |
| 14 | 885821206052908125 |
| 15 | 50491808745015763125 |
| 16 | 3080000333445961550625 |
| 17 | 200200021673987500790625 |
| 18 | 13813801495505137554553125 |
[1,1,5,45,585,9945,208845,5221125,151412625, 4996616625,184874815125,7579867420125, 341094033905625,16713607661375625, 885821206052908125,50491808745015763125, 3080000333445961550625,200200021673987500790625, 13813801495505137554553125] |