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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 6 |
| 4 | 15 |
| 5 | 43 |
| 6 | 133 |
| 7 | 430 |
| 8 | 1431 |
| 9 | 4863 |
| 10 | 16797 |
| 11 | 58787 |
| 12 | 208013 |
| 13 | 742901 |
| 14 | 2674441 |
| 15 | 9694846 |
| 16 | 35357671 |
| 17 | 129644791 |
| 18 | 477638701 |
| 19 | 1767263191 |
| 20 | 6564120421 |
| 21 | 24466267021 |
| 22 | 91482563641 |
| 23 | 343059613651 |
| 24 | 1289904147325 |
| 25 | 4861946401453 |
| 26 | 18367353072153 |
| 27 | 69533550916005 |
[1,2,3,6,15,43,133,430,1431,4863,16797,58787, 208013,742901,2674441,9694846,35357671,129644791, 477638701,1767263191,6564120421,24466267021, 91482563641,343059613651,1289904147325, 4861946401453,18367353072153,69533550916005] |