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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 13 |
| 4 | 31 |
| 5 | 84 |
| 6 | 271 |
| 7 | 1111 |
| 8 | 6096 |
| 9 | 44965 |
| 10 | 434321 |
| 11 | 5388944 |
| 12 | 85434621 |
| 13 | 1727597731 |
| 14 | 44466614106 |
| 15 | 1455616862597 |
| 16 | 60619117448531 |
| 17 | 3211943842710212 |
| 18 | 216483614502128251 |
| 19 | 18558646821817827015 |
| 20 | 2023790814160269113876 |
| 21 | 280732940929438329958733 |
| 22 | 49535201863823517417076181 |
[1,3,6,13,31,84,271,1111,6096,44965,434321, 5388944,85434621,1727597731,44466614106, 1455616862597,60619117448531,3211943842710212, 216483614502128251,18558646821817827015, 2023790814160269113876,280732940929438329958733, 49535201863823517417076181] |