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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1344 |
| 3 | 12960 |
| 4 | 118584 |
| 5 | 1004184 |
| 6 | 8250912 |
| 7 | 66210264 |
| 8 | 522241560 |
| 9 | 4063962024 |
| 10 | 31282792704 |
| 11 | 238663638432 |
| 12 | 1807307152056 |
| 13 | 13599932970888 |
| 14 | 101786388133320 |
| 15 | 758232651966984 |
| 16 | 5625079743143376 |
| 17 | 41579318178922608 |
| 18 | 306353541215271960 |
[0,1344,12960,118584,1004184,8250912,66210264, 522241560,4063962024,31282792704,238663638432, 1807307152056,13599932970888,101786388133320, 758232651966984,5625079743143376, 41579318178922608,306353541215271960] |