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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 36 |
| 3 | 800 |
| 4 | 1568 |
| 5 | 290304 |
| 6 | 123904 |
| 7 | 15228928 |
| 8 | 8785920 |
| 9 | 492437504 |
| 10 | 1608777728 |
| 11 | 99574874112 |
| 12 | 2508338495488 |
| 13 | 9164554240000 |
| 14 | 106895360655360 |
| 15 | 31154082152448 |
| 16 | 430159094087680 |
| 17 | 580265191384547328 |
| 18 | 148655260565504000 |
| 19 | 1860654187101028352 |
| 20 | 20860356402314477568 |
[2,36,800,1568,290304,123904,15228928,8785920, 492437504,1608777728,99574874112,2508338495488, 9164554240000,106895360655360,31154082152448, 430159094087680,580265191384547328, 148655260565504000,1860654187101028352, 20860356402314477568] |