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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 75 |
| 6 | 265 |
| 7 | 929 |
| 8 | 3249 |
| 9 | 11362 |
| 10 | 39746 |
| 11 | 139060 |
| 12 | 486549 |
| 13 | 1702349 |
| 14 | 5956172 |
| 15 | 20839367 |
| 16 | 72912441 |
| 17 | 255104933 |
| 18 | 892557394 |
| 19 | 3122866871 |
| 20 | 10926241348 |
| 21 | 38228574601 |
| 22 | 133753581322 |
| 23 | 467975086412 |
| 24 | 1637344431204 |
| 25 | 5728716901208 |
[1,2,6,21,75,265,929,3249,11362,39746,139060, 486549,1702349,5956172,20839367,72912441, 255104933,892557394,3122866871,10926241348, 38228574601,133753581322,467975086412, 1637344431204,5728716901208] |