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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 17 |
| 4 | 142 |
| 5 | 1569 |
| 6 | 21576 |
| 7 | 355081 |
| 8 | 6805296 |
| 9 | 148869153 |
| 10 | 3660215680 |
| 11 | 99920609601 |
| 12 | 2998836525312 |
| 13 | 98139640241473 |
| 14 | 3478081490967552 |
| 15 | 132705415800984825 |
| 16 | 5423640496274200576 |
| 17 | 236389784118231290049 |
| 18 | 10944997108429625524224 |
| 19 | 536484538620663729658993 |
[1,3,17,142,1569,21576,355081,6805296,148869153, 3660215680,99920609601,2998836525312, 98139640241473,3478081490967552, 132705415800984825,5423640496274200576, 236389784118231290049,10944997108429625524224, 536484538620663729658993] |