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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 56 |
| 4 | 304 |
| 5 | 1632 |
| 6 | 9024 |
| 7 | 50304 |
| 8 | 283392 |
| 9 | 1607168 |
| 10 | 9167872 |
| 11 | 52537344 |
| 12 | 302239744 |
| 13 | 1744412672 |
| 14 | 10096263168 |
| 15 | 58576306176 |
| 16 | 340566147072 |
| 17 | 1983765676032 |
| 18 | 11574393962496 |
| 19 | 67631502065664 |
| 20 | 395710949228544 |
| 21 | 2318088492023808 |
| 22 | 13594307705438208 |
| 23 | 79802741538422784 |
| 24 | 468895276304695296 |
[1,2,12,56,304,1632,9024,50304,283392,1607168, 9167872,52537344,302239744,1744412672,10096263168, 58576306176,340566147072,1983765676032, 11574393962496,67631502065664,395710949228544, 2318088492023808,13594307705438208, 79802741538422784,468895276304695296] |