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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 21 |
| 4 | 95 |
| 5 | 405 |
| 6 | 1680 |
| 7 | 6926 |
| 8 | 28257 |
| 9 | 115254 |
| 10 | 471785 |
| 11 | 1908622 |
| 12 | 7444553 |
| 13 | 27617809 |
| 14 | 101165030 |
| 15 | 411727344 |
| 16 | 1980777419 |
| 17 | 9377434309 |
| 18 | 30465401498 |
| 19 | 5465053256 |
| 20 | -319249451709 |
| 21 | 3800908753389 |
| 22 | 79369582680985 |
| 23 | 507720631888326 |
| 24 | -779604798853789 |
| 25 | -39876367011094054 |
[1,1,5,21,95,405,1680,6926,28257,115254,471785, 1908622,7444553,27617809,101165030,411727344, 1980777419,9377434309,30465401498,5465053256, -319249451709,3800908753389,79369582680985, 507720631888326,-779604798853789, -39876367011094054] |