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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 19 |
| 7 | 59 |
| 8 | 267 |
| 9 | 1380 |
| 10 | 9832 |
| 11 | 90842 |
| 12 | 1144061 |
| 13 | 19425052 |
| 14 | 445781050 |
| 15 | 13743625184 |
| 16 | 566756900370 |
| 17 | 31125101479652 |
[1,1,1,3,6,19,59,267,1380,9832,90842,1144061, 19425052,445781050,13743625184,566756900370, 31125101479652] |