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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 39 |
| 7 | 282 |
| 8 | 2476 |
| 9 | 25468 |
| 10 | 300104 |
| 11 | 3984742 |
| 12 | 58857048 |
| 13 | 957156654 |
| 14 | 16992957454 |
| 15 | 327018332848 |
| 16 | 6780662275976 |
| 17 | 150700528101856 |
| 18 | 3573879622264536 |
| 19 | 90079771978313256 |
| 20 | 2404666535666287000 |
| 21 | 67774524657985373248 |
| 22 | 2011157217480732750512 |
| 23 | 62675350084052135287072 |
[1,1,1,2,7,39,282,2476,25468,300104,3984742, 58857048,957156654,16992957454,327018332848, 6780662275976,150700528101856,3573879622264536, 90079771978313256,2404666535666287000, 67774524657985373248,2011157217480732750512, 62675350084052135287072] |