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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 8 |
| 6 | 24 |
| 7 | 56 |
| 8 | 168 |
| 9 | 432 |
| 10 | 1320 |
| 11 | 3608 |
| 12 | 11216 |
| 13 | 31952 |
| 14 | 100720 |
| 15 | 295600 |
| 16 | 942272 |
| 17 | 2828112 |
| 18 | 9097256 |
| 19 | 27785112 |
| 20 | 90048656 |
| 21 | 278899152 |
| 22 | 909566560 |
| 23 | 2849498656 |
| 24 | 9342566152 |
| 25 | 29548420688 |
| 26 | 97323261664 |
[1,2,4,8,24,56,168,432,1320,3608,11216,31952, 100720,295600,942272,2828112,9097256,27785112, 90048656,278899152,909566560,2849498656, 9342566152,29548420688,97323261664] |