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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 52 |
| 5 | 362 |
| 6 | 2779 |
| 7 | 23749 |
| 8 | 224570 |
| 9 | 2334827 |
| 10 | 26504418 |
| 11 | 326476313 |
| 12 | 4338953453 |
| 13 | 61908434299 |
| 14 | 944065986251 |
| 15 | 15325676747363 |
| 16 | 263910466293264 |
| 17 | 4805394642545408 |
| 18 | 92254524334410750 |
| 19 | 1862526899218400010 |
| 20 | 39449927915059031609 |
| 21 | 874745258339527435041 |
| 22 | 20265180489604116160763 |
[0,1,8,52,362,2779,23749,224570,2334827,26504418, 326476313,4338953453,61908434299,944065986251, 15325676747363,263910466293264,4805394642545408, 92254524334410750,1862526899218400010, 39449927915059031609,874745258339527435041, 20265180489604116160763] |