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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 21 |
| 4 | 296 |
| 5 | 5677 |
| 6 | 291348 |
| 7 | 22679763 |
| 8 | 3946629792 |
| 9 | 1281287791090 |
| 10 | 840017139222515 |
| 11 | 1068253745514088673 |
| 12 | 2745322115165570881474 |
| 13 | 14006438682727577999625359 |
| 14 | 141884380264686466724199980066 |
| 15 | 2897075017978846591982107951045864 |
| 16 | 118770312781918226439371316982748736112 |
[1,1,4,21,296,5677,291348,22679763,3946629792, 1281287791090,840017139222515,1068253745514088673, 2745322115165570881474,14006438682727577999625359, 141884380264686466724199980066, 2897075017978846591982107951045864, 118770312781918226439371316982748736112] |