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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 23 |
| 4 | 103 |
| 5 | 512 |
| 6 | 2740 |
| 7 | 15485 |
| 8 | 91245 |
| 9 | 555662 |
| 10 | 3475090 |
| 11 | 22214707 |
| 12 | 144640291 |
| 13 | 956560748 |
| 14 | 6411521056 |
| 15 | 43478151737 |
| 16 | 297864793993 |
| 17 | 2059159989914 |
| 18 | 14350039389022 |
| 19 | 100726680316559 |
| 20 | 711630547589023 |
| 21 | 5057282786190872 |
| 22 | 36132861123763276 |
| 23 | 259423620328055093 |
| 24 | 1870954187618001253 |
[1,2,6,23,103,512,2740,15485,91245,555662,3475090, 22214707,144640291,956560748,6411521056, 43478151737,297864793993,2059159989914, 14350039389022,100726680316559,711630547589023, 5057282786190872,36132861123763276, 259423620328055093,1870954187618001253] |