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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 44 |
| 5 | 1333 |
| 6 | 467721009 |
| 7 | 1030285482262444082798370 |
| 8 | 10783320970547639134314329603627596568605613243959124417106 |
[2,4,10,44,1333,467721009, 1030285482262444082798370, 10783320970547639134314329603627596568605613243959\ 124417106] |