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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 96 |
| 5 | 1385 |
| 6 | 22080 |
| 7 | 403417 |
| 8 | 8829184 |
| 9 | 227956689 |
| 10 | 6667822080 |
| 11 | 215780258441 |
| 12 | 7674505073664 |
| 13 | 298885308910201 |
| 14 | 12661212551163904 |
| 15 | 578940699178779225 |
| 16 | 28400662193828659200 |
| 17 | 1488075298726340008097 |
| 18 | 82965096417136263561216 |
| 19 | 4904558063539270185865609 |
[1,1,2,9,96,1385,22080,403417,8829184,227956689, 6667822080,215780258441,7674505073664, 298885308910201,12661212551163904, 578940699178779225,28400662193828659200, 1488075298726340008097,82965096417136263561216, 4904558063539270185865609] |