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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 8 |
| 4 | 144 |
| 5 | 4554 |
| 6 | 230940 |
| 7 | 18177900 |
| 8 | 2196712980 |
| 9 | 406693854000 |
| 10 | 115319921466960 |
| 11 | 50017977456121080 |
| 12 | 33099984846144881280 |
| 13 | 33309128229289401091680 |
| 14 | 50790831819884758635873840 |
| 15 | 116936359809482874588941613600 |
| 16 | 405126119455062475269210516705600 |
[1,1,8,144,4554,230940,18177900,2196712980, 406693854000,115319921466960,50017977456121080, 33099984846144881280,33309128229289401091680, 50790831819884758635873840, 116936359809482874588941613600, 405126119455062475269210516705600] |