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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 45 |
| 5 | 148 |
| 6 | 502 |
| 7 | 1766 |
| 8 | 6432 |
| 9 | 23753 |
| 10 | 89949 |
| 11 | 344107 |
| 12 | 1337603 |
| 13 | 5257450 |
| 14 | 20867047 |
| 15 | 83699338 |
| 16 | 337925520 |
| 17 | 1376164889 |
| 18 | 5635244713 |
| 19 | 23226831515 |
| 20 | 96241844903 |
| 21 | 400714413394 |
| 22 | 1676717147085 |
| 23 | 7042517238362 |
| 24 | 29708580384864 |
| 25 | 125739464072768 |
| 26 | 534100530069694 |
| 27 | 2275729997688530 |
| 28 | 9724986583465393 |
[1,2,5,15,45,148,502,1766,6432,23753,89949,344107, 1337603,5257450,20867047,83699338,337925520, 1376164889,5635244713,23226831515,96241844903, 400714413394,1676717147085,7042517238362, 29708580384864,125739464072768,534100530069694, 2275729997688530,9724986583465393] |