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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 45 |
| 4 | 1095 |
| 5 | 35151 |
| 6 | 1381725 |
| 7 | 64175631 |
| 8 | 3451040205 |
| 9 | 211905683649 |
| 10 | 14692740175359 |
| 11 | 1138932255875229 |
| 12 | 97794610588861299 |
| 13 | 9222742814262416391 |
| 14 | 947982726689249684721 |
| 15 | 105483448180468629244791 |
| 16 | 12630764358798125298488577 |
| 17 | 1619156615552164362662455257 |
| 18 | 221209937165123652082161577203 |
[1,1,3,45,1095,35151,1381725,64175631,3451040205, 211905683649,14692740175359,1138932255875229, 97794610588861299,9222742814262416391, 947982726689249684721,105483448180468629244791, 12630764358798125298488577, 1619156615552164362662455257, 221209937165123652082161577203] |