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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 2 |
| 7 | 5 |
| 8 | 14 |
| 9 | 50 |
| 10 | 233 |
| 11 | 1249 |
| 12 | 7595 |
| 13 | 49566 |
| 14 | 339722 |
| 15 | 2406841 |
| 16 | 17490241 |
| 17 | 129664753 |
| 18 | 977526957 |
| 19 | 7475907149 |
| 20 | 57896349553 |
| 21 | 453382272049 |
| 22 | 3585853662949 |
| 23 | 28615703421545 |
[1,1,1,2,5,14,50,233,1249,7595,49566,339722, 2406841,17490241,129664753,977526957,7475907149, 57896349553,453382272049,3585853662949, 28615703421545] |