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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 168 |
| 3 | 420 |
| 4 | 5460 |
| 5 | 14560 |
| 6 | 276640 |
| 7 | 3043040 |
| 8 | 136936800 |
| 9 | 136936800 |
| 10 | 4245040800 |
| 11 | 72165693600 |
| 12 | 2670130663200 |
| 13 | 2670130663200 |
| 14 | 114815618517600 |
| 15 | 1320379612952400 |
| 16 | 9242657290666800 |
| 17 | 3080885763555600 |
| 18 | 280080523959600 |
| 19 | 8122335194828400 |
| 20 | 165154148961510800 |
| 21 | 14533565108612950400 |
| 22 | 973748862277067676800 |
[1,8,168,420,5460,14560,276640,3043040,136936800, 136936800,4245040800,72165693600,2670130663200, 2670130663200,114815618517600,1320379612952400, 9242657290666800,3080885763555600,280080523959600, 8122335194828400,165154148961510800, 14533565108612950400,973748862277067676800] |