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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 6 |
| 4 | 22 |
| 5 | 224 |
| 6 | 88 |
| 7 | 984 |
| 8 | 2320 |
| 9 | 10896 |
| 10 | 79296 |
| 11 | 98064 |
| 12 | 811728 |
| 13 | 2506032 |
| 14 | 14823648 |
| 15 | 109131840 |
| 16 | 59294592 |
| 17 | 495821952 |
| 18 | 1228822272 |
| 19 | 5669754624 |
| 20 | 5669754624 |
| 21 | 5669754624 |
| 22 | 5669754624 |
| 23 | 5669754624 |
| 24 | 5669754624 |
| 25 | 69265877760 |
| 26 | 132862000896 |
[1,1,6,22,224,88,984,2320,10896,79296,98064, 811728,2506032,14823648,109131840,59294592, 495821952,1228822272,5669754624,5669754624, 5669754624,5669754624,5669754624,5669754624, 69265877760,132862000896] |