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| n | a(n) |
|---|---|
| 4 | 4 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 56 |
| 9 | 144 |
| 10 | 180 |
| 11 | 220 |
| 12 | 1716 |
| 13 | 5928 |
| 14 | 14560 |
| 15 | 26880 |
| 16 | 97680 |
| 17 | 344352 |
| 18 | 978588 |
| 19 | 2346120 |
| 20 | 7444580 |
| 21 | 25763640 |
| 22 | 79547622 |
| 23 | 213434848 |
| 24 | 663024312 |
| 25 | 2288434800 |
| 26 | 7496808800 |
| 27 | 21967834824 |
| 28 | 68476484916 |
| 29 | 235311849416 |
| 30 | 802176548700 |
| 31 | 2519791766160 |
| 32 | 8048777883936 |
[4,0,0,0,56,144,180,220,1716,5928,14560,26880, 97680,344352,978588,2346120,7444580,25763640, 79547622,213434848,663024312,2288434800, 7496808800,21967834824,68476484916,235311849416, 802176548700,2519791766160,8048777883936] |