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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 6 |
| 2 | 168 |
| 3 | 4374 |
| 4 | 113568 |
| 5 | 2948406 |
| 6 | 76545000 |
| 7 | 1987221606 |
| 8 | 51591216768 |
| 9 | 1339384414374 |
| 10 | 34772403556968 |
| 11 | 902743108066806 |
| 12 | 23436548406180000 |
| 13 | 608447515452613206 |
| 14 | 15796198853361763368 |
| 15 | 410092722671953234374 |
| 16 | 10646614590617422330368 |
| 17 | 276401886633381027355206 |
[0,6,168,4374,113568,2948406,76545000,1987221606, 51591216768,1339384414374,34772403556968, 902743108066806,23436548406180000, 608447515452613206,15796198853361763368, 410092722671953234374,10646614590617422330368, 276401886633381027355206] |