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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 10 |
| 4 | 105 |
| 5 | 840 |
| 6 | 5775 |
| 7 | 36036 |
| 8 | 210210 |
| 9 | 1166880 |
| 10 | 6235515 |
| 11 | 32332300 |
| 12 | 163601438 |
| 13 | 811246800 |
| 14 | 3954828150 |
| 15 | 19001896200 |
| 16 | 90162058500 |
| 17 | 423160594560 |
| 18 | 1967035576275 |
| 19 | 9066060164700 |
| 20 | 41468830753350 |
| 21 | 188390256054000 |
| 22 | 850582006083810 |
| 23 | 3818939619151800 |
| 24 | 17058982348359900 |
[0,0,10,105,840,5775,36036,210210,1166880,6235515, 32332300,163601438,811246800,3954828150, 19001896200,90162058500,423160594560, 1967035576275,9066060164700,41468830753350, 188390256054000,850582006083810,3818939619151800, 17058982348359900] |