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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 7 |
| 4 | 61 |
| 5 | 751 |
| 6 | 12181 |
| 7 | 237007 |
| 8 | 5489821 |
| 9 | 146316751 |
| 10 | 4421327461 |
| 11 | 149295669007 |
| 12 | 5571151966381 |
| 13 | 227686268177551 |
| 14 | 10113730235530741 |
| 15 | 485169897369011407 |
| 16 | 24997456057660894141 |
| 17 | 1376733652387749583951 |
| 18 | 80713621007842818156421 |
| 19 | 5018684662081500344862607 |
[1,1,7,61,751,12181,237007,5489821,146316751, 4421327461,149295669007,5571151966381, 227686268177551,10113730235530741, 485169897369011407,24997456057660894141, 1376733652387749583951,80713621007842818156421, 5018684662081500344862607] |