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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 55 |
| 2 | 3486 |
| 3 | 281210 |
| 4 | 28862471 |
| 5 | 3706931865 |
| 6 | 584856590956 |
| 7 | 111432850130020 |
| 8 | 25255179275602941 |
| 9 | 6719606199432053675 |
| 10 | 2074965724098955112426 |
| 11 | 736196253336729035680830 |
| 12 | 297480985088238886530733411 |
[1,55,3486,281210,28862471,3706931865, 584856590956,111432850130020,25255179275602941, 6719606199432053675,2074965724098955112426, 736196253336729035680830, 297480985088238886530733411] |