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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 61 |
| 4 | 619 |
| 5 | 7045 |
| 6 | 87955 |
| 7 | 1187845 |
| 8 | 17192275 |
| 9 | 264940405 |
| 10 | 4326439075 |
| 11 | 74593075525 |
| 12 | 1353928981075 |
| 13 | 25809901069525 |
| 14 | 515683999204675 |
| 15 | 10779677853137125 |
| 16 | 235366439343773875 |
| 17 | 5359766538695291125 |
[1,1,7,61,619,7045,87955,1187845,17192275, 264940405,4326439075,74593075525,1353928981075, 25809901069525,515683999204675,10779677853137125, 235366439343773875,5359766538695291125] |