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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 20 |
| 4 | 114 |
| 5 | 529 |
| 6 | 3050 |
| 7 | 16333 |
| 8 | 96291 |
| 9 | 554489 |
| 10 | 3343913 |
| 11 | 20074658 |
| 12 | 123474818 |
| 13 | 761154695 |
| 14 | 4758617798 |
| 15 | 29876386844 |
| 16 | 189275072084 |
| 17 | 1204491672779 |
| 18 | 7713591678563 |
| 19 | 49602001416920 |
| 20 | 320478996972260 |
| 21 | 2078111745252647 |
| 22 | 13525786891484513 |
| 23 | 88309928176783985 |
| 24 | 578342399955533489 |
| 25 | 3797738127548969927 |
[1,1,6,20,114,529,3050,16333,96291,554489,3343913, 20074658,123474818,761154695,4758617798, 29876386844,189275072084,1204491672779, 7713591678563,49602001416920,320478996972260, 2078111745252647,13525786891484513, 88309928176783985,578342399955533489, 3797738127548969927] |