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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 75 |
| 6 | 266 |
| 7 | 935 |
| 8 | 3263 |
| 9 | 11326 |
| 10 | 39155 |
| 11 | 134955 |
| 12 | 464094 |
| 13 | 1593231 |
| 14 | 5462447 |
| 15 | 18709694 |
| 16 | 64035275 |
| 17 | 219039523 |
| 18 | 748919582 |
| 19 | 2559777591 |
| 20 | 8746974087 |
| 21 | 29883271518 |
| 22 | 102078226067 |
| 23 | 348648695387 |
| 24 | 1190706243710 |
| 25 | 4066228992799 |
[1,2,6,21,75,266,935,3263,11326,39155,134955, 464094,1593231,5462447,18709694,64035275, 219039523,748919582,2559777591,8746974087, 29883271518,102078226067,348648695387, 1190706243710,4066228992799] |