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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 6 |
| 5 | 10 |
| 6 | 27 |
| 7 | 55 |
| 8 | 171 |
| 9 | 475 |
| 10 | 1555 |
| 11 | 4915 |
| 12 | 20023 |
| 13 | 68243 |
| 14 | 288024 |
| 15 | 1213828 |
| 16 | 5435935 |
| 17 | 23966970 |
| 18 | 121432923 |
| 19 | 578757824 |
| 20 | 3130381590 |
| 21 | 16427772974 |
| 22 | 91877826663 |
| 23 | 519546134163 |
| 24 | 3199523135912 |
| 25 | 18868494152257 |
| 26 | 120274458082095 |
| 27 | 772954621249540 |
| 28 | 5219747666882153 |
[1,1,2,3,6,10,27,55,171,475,1555,4915,20023,68243, 288024,1213828,5435935,23966970,121432923, 578757824,3130381590,16427772974,91877826663, 519546134163,3199523135912,18868494152257, 120274458082095,772954621249540,5219747666882153] |