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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | 1 |
| 2 | 12 |
| 3 | 25 |
| 4 | 61 |
| 5 | 266 |
| 6 | 963 |
| 7 | 3053 |
| 8 | 10220 |
| 9 | 35413 |
| 10 | 120345 |
| 11 | 405682 |
| 12 | 1376119 |
| 13 | 4676201 |
| 14 | 15859212 |
| 15 | 53768225 |
| 16 | 182400581 |
| 17 | 618792826 |
| 18 | 2098887003 |
| 19 | 7119249973 |
| 20 | 24149097580 |
| 21 | 81915342653 |
| 22 | 277858469505 |
| 23 | 942504046562 |
| 24 | 3197013067439 |
| 25 | 10844389616401 |
| 26 | 36784545696012 |
[-1,1,12,25,61,266,963,3053,10220,35413,120345, 405682,1376119,4676201,15859212,53768225, 182400581,618792826,2098887003,7119249973, 24149097580,81915342653,277858469505,942504046562, 3197013067439,10844389616401,36784545696012] |