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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 5 |
| 5 | 13 |
| 6 | 38 |
| 7 | 58 |
| 8 | 191 |
| 9 | 655 |
| 10 | 2374 |
| 11 | 4462 |
| 12 | 17519 |
| 13 | 71063 |
| 14 | 298810 |
| 15 | 646846 |
| 16 | 2887921 |
| 17 | 13237457 |
| 18 | 62332114 |
| 19 | 150303170 |
| 20 | 742458253 |
| 21 | 3748521653 |
| 22 | 19340144966 |
| 23 | 50903810666 |
| 24 | 273315477775 |
| 25 | 1495006933759 |
| 26 | 8327893878134 |
| 27 | 23599037077934 |
[1,1,2,2,5,13,38,58,191,655,2374,4462,17519,71063, 298810,646846,2887921,13237457,62332114,150303170, 742458253,3748521653,19340144966,50903810666, 273315477775,1495006933759,8327893878134, 23599037077934] |