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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 26 |
| 6 | 77 |
| 7 | 235 |
| 8 | 758 |
| 9 | 2504 |
| 10 | 8483 |
| 11 | 29203 |
| 12 | 102030 |
| 13 | 360442 |
| 14 | 1285926 |
| 15 | 4625102 |
| 16 | 16754302 |
| 17 | 61067430 |
| 18 | 223803775 |
| 19 | 824188993 |
| 20 | 3048383517 |
| 21 | 11318928477 |
| 22 | 42176798315 |
| 23 | 157664823501 |
| 24 | 591109863049 |
| 25 | 2222121888117 |
| 26 | 8374151243258 |
| 27 | 31630394287364 |
| 28 | 119725350703472 |
[1,1,2,4,10,26,77,235,758,2504,8483,29203,102030, 360442,1285926,4625102,16754302,61067430, 223803775,824188993,3048383517,11318928477, 42176798315,157664823501,591109863049, 2222121888117,8374151243258,31630394287364, 119725350703472] |