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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 51 |
| 5 | 201 |
| 6 | 825 |
| 7 | 3431 |
| 8 | 14355 |
| 9 | 60493 |
| 10 | 256463 |
| 11 | 1092268 |
| 12 | 4669665 |
| 13 | 20029036 |
| 14 | 86148373 |
| 15 | 371434173 |
| 16 | 1604845715 |
| 17 | 6946936628 |
| 18 | 30121158813 |
| 19 | 130795358333 |
| 20 | 568709929191 |
| 21 | 2475778867547 |
| 22 | 10789659781640 |
| 23 | 47069225185789 |
| 24 | 205524447217185 |
| 25 | 898163031782576 |
| 26 | 3928112419640126 |
[1,1,3,13,51,201,825,3431,14355,60493,256463, 1092268,4669665,20029036,86148373,371434173, 1604845715,6946936628,30121158813,130795358333, 568709929191,2475778867547,10789659781640, 47069225185789,205524447217185,898163031782576, 3928112419640126] |