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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 20 |
| 4 | 350 |
| 5 | 140 |
| 6 | 1050 |
| 7 | 300 |
| 8 | 57750 |
| 9 | 38500 |
| 10 | 250250 |
| 11 | 45500 |
| 12 | 2388750 |
| 13 | 367500 |
| 14 | 318750 |
| 15 | 42500 |
| 16 | 1088106250 |
| 17 | 128012500 |
| 18 | 960093750 |
| 19 | 101062500 |
| 20 | 105761906250 |
| 21 | 10072562500 |
| 22 | 2289218750 |
| 23 | 199062500 |
| 24 | 8842968750 |
| 25 | 707437500 |
| 26 | 51289218750 |
[1,2,5,20,350,140,1050,300,57750,38500,250250, 45500,2388750,367500,318750,42500,1088106250, 128012500,960093750,101062500,105761906250, 10072562500,2289218750,199062500,8842968750, 707437500,51289218750] |