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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 2 |
| 6 | 6 |
| 7 | 2 |
| 8 | 18 |
| 9 | 54 |
| 10 | 30 |
| 11 | 36 |
| 12 | 576 |
| 13 | 127 |
| 14 | 840 |
| 15 | 928 |
| 16 | 3712 |
| 17 | 20160 |
| 18 | 93696 |
| 19 | 420480 |
| 20 | 800640 |
| 21 | 1305696 |
| 22 | 7983360 |
| 23 | 55056804 |
| 24 | 65318400 |
| 25 | 326592000 |
| 26 | 2286926400 |
| 27 | 2610934480 |
| 28 | 13680979200 |
| 29 | 18906930876 |
| 30 | 674165366496 |
| 31 | 326850970500 |
| 32 | 16753029012720 |
| 33 | 16880461678080 |
[0,1,1,2,2,6,2,18,54,30,36,576,127,840,928,3712, 20160,93696,420480,800640,1305696,7983360, 55056804,65318400,326592000,2286926400,2610934480, 13680979200,18906930876,674165366496,326850970500, 16753029012720,16880461678080] |