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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 11 |
| 3 | 55 |
| 4 | 315 |
| 5 | 1871 |
| 6 | 11203 |
| 7 | 67191 |
| 8 | 403115 |
| 9 | 2418655 |
| 10 | 14511891 |
| 11 | 87071303 |
| 12 | 522427771 |
| 13 | 3134566575 |
| 14 | 18807399395 |
| 15 | 112844396311 |
| 16 | 677066377803 |
| 17 | 4062398266751 |
| 18 | 24374389600435 |
| 19 | 146246337602535 |
| 20 | 877478025615131 |
| 21 | 5264868153690703 |
| 22 | 31589208922144131 |
| 23 | 189535253532864695 |
[1,3,11,55,315,1871,11203,67191,403115,2418655, 14511891,87071303,522427771,3134566575, 18807399395,112844396311,677066377803, 4062398266751,24374389600435,146246337602535, 877478025615131,5264868153690703, 31589208922144131,189535253532864695] |