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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 20 |
| 3 | 104 |
| 4 | 464 |
| 5 | 650 |
| 6 | 1952 |
| 7 | 130304 |
| 8 | 522752 |
| 9 | 8382464 |
| 10 | 134193152 |
| 11 | 549754241024 |
| 12 | 8796086730752 |
| 13 | 140737463189504 |
[1,20,104,464,650,1952,130304,522752,8382464, 134193152,549754241024,8796086730752, 140737463189504] |