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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 61 |
| 6 | 280 |
| 7 | 1501 |
| 8 | 9394 |
| 9 | 68647 |
| 10 | 591570 |
| 11 | 6108298 |
| 12 | 77162708 |
| 13 | 1219779207 |
| 14 | 24648006828 |
| 15 | 647865966973 |
| 16 | 22437052221282 |
| 17 | 1032905858402302 |
| 18 | 63591727342096158 |
| 19 | 5258562027225785955 |
| 20 | 586001891321599337103 |
| 21 | 88241281449605821921186 |
| 22 | 17996565026907866304071630 |
[1,1,2,5,16,61,280,1501,9394,68647,591570,6108298, 77162708,1219779207,24648006828,647865966973, 22437052221282,1032905858402302,63591727342096158, 5258562027225785955,586001891321599337103, 88241281449605821921186, 17996565026907866304071630] |