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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 1211 |
| 4 | 6907736 |
| 5 | 423503301834 |
| 6 | 274342896958292170 |
| 7 | 1877611081501313948217870 |
| 8 | 135766460737448561825230968357842 |
[1,4,1211,6907736,423503301834,274342896958292170, 1877611081501313948217870, 135766460737448561825230968357842] |