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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 528 |
| 3 | 29646 |
| 4 | 524800 |
| 5 | 4884375 |
| 6 | 30236976 |
| 7 | 141246028 |
| 8 | 536887296 |
| 9 | 1743421725 |
| 10 | 5000050000 |
| 11 | 12968792826 |
| 12 | 30958806528 |
| 13 | 68929431571 |
| 14 | 144627596400 |
| 15 | 288325575000 |
| 16 | 549756338176 |
| 17 | 1007997660153 |
| 18 | 1785234558096 |
| 19 | 3065534366950 |
| 20 | 5120001600000 |
| 21 | 8339942531151 |
[0,1,528,29646,524800,4884375,30236976,141246028, 536887296,1743421725,5000050000,12968792826, 30958806528,68929431571,144627596400,288325575000, 549756338176,1007997660153,1785234558096, 3065534366950,5120001600000,8339942531151] |