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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 2 |
| 3 | 12 |
| 4 | 76 |
| 5 | 504 |
| 6 | 3472 |
| 7 | 24672 |
| 8 | 179792 |
| 9 | 1337376 |
| 10 | 10117312 |
| 11 | 77618304 |
| 12 | 602528640 |
| 13 | 4724294400 |
| 14 | 37361809920 |
| 15 | 297683352576 |
| 16 | 2387325283584 |
| 17 | 19255919325696 |
| 18 | 156110855965696 |
| 19 | 1271401468151808 |
[3,2,12,76,504,3472,24672,179792,1337376,10117312, 77618304,602528640,4724294400,37361809920, 297683352576,2387325283584,19255919325696, 156110855965696,1271401468151808] |