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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 3 | 54 |
| 4 | 252 |
| 5 | 1110 |
| 6 | 4748 |
| 7 | 19964 |
| 8 | 83024 |
| 9 | 342678 |
| 10 | 1406748 |
| 11 | 5751636 |
| 12 | 23443240 |
| 13 | 95319484 |
| 14 | 386805112 |
| 15 | 1567130168 |
| 16 | 6340730552 |
| 17 | 25626393878 |
| 18 | 103472018492 |
| 19 | 417449893988 |
| 20 | 1682982404072 |
| 21 | 6780908053268 |
| 22 | 27306234108392 |
| 23 | 109907864408648 |
[1,10,54,252,1110,4748,19964,83024,342678,1406748, 5751636,23443240,95319484,386805112,1567130168, 6340730552,25626393878,103472018492,417449893988, 1682982404072,6780908053268,27306234108392, 109907864408648] |