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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 14 |
| 3 | 204 |
| 4 | 5016 |
| 5 | 185520 |
| 6 | 9595440 |
| 7 | 659846880 |
| 8 | 58130513280 |
| 9 | 6376568728320 |
| 10 | 851542303852800 |
| 11 | 135930981520857600 |
| 12 | 25547289000870067200 |
| 13 | 5581430113409537587200 |
| 14 | 1402137089367777207244800 |
| 15 | 401230026747563176171008000 |
| 16 | 129714370868892377008336896000 |
[1,2,14,204,5016,185520,9595440,659846880, 58130513280,6376568728320,851542303852800, 135930981520857600,25547289000870067200, 5581430113409537587200,1402137089367777207244800, 401230026747563176171008000, 129714370868892377008336896000] |