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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 65 |
| 5 | 369 |
| 6 | 3139 |
| 7 | 24667 |
| 8 | 268449 |
| 9 | 2777345 |
| 10 | 34932131 |
| 11 | 432114891 |
| 12 | 6790407073 |
| 13 | 97969389361 |
| 14 | 1671204338595 |
| 15 | 28382893729499 |
| 16 | 557174580764609 |
| 17 | 10512263160373377 |
| 18 | 228918738980395459 |
| 19 | 4817409763554888715 |
| 20 | 115117419384636141441 |
| 21 | 2688602544800222293361 |
[1,1,3,11,65,369,3139,24667,268449,2777345, 34932131,432114891,6790407073,97969389361, 1671204338595,28382893729499,557174580764609, 10512263160373377,228918738980395459, 4817409763554888715,115117419384636141441, 2688602544800222293361] |