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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 8 |
| 6 | 19 |
| 7 | 57 |
| 8 | 186 |
| 9 | 740 |
| 10 | 3389 |
| 11 | 18502 |
| 12 | 120221 |
| 13 | 932260 |
| 14 | 8596844 |
| 15 | 93762704 |
| 16 | 1201732437 |
| 17 | 17992683043 |
| 18 | 313098431306 |
| 19 | 6305419392541 |
[1,1,2,3,8,19,57,186,740,3389,18502,120221,932260, 8596844,93762704,1201732437,17992683043, 313098431306,6305419392541] |