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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 123 |
| 5 | 1221 |
| 6 | 14724 |
| 7 | 207908 |
| 8 | 3355803 |
| 9 | 60873595 |
| 10 | 1225319163 |
| 11 | 27097430328 |
| 12 | 653052022740 |
| 13 | 17036213760892 |
| 14 | 478306368143880 |
| 15 | 14381009543824236 |
| 16 | 461038595072589531 |
| 17 | 15699544671941958663 |
| 18 | 565927686301436324649 |
[1,1,3,16,123,1221,14724,207908,3355803,60873595, 1225319163,27097430328,653052022740, 17036213760892,478306368143880,14381009543824236, 461038595072589531,15699544671941958663, 565927686301436324649] |