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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 84 |
| 5 | 320 |
| 6 | 1262 |
| 7 | 5098 |
| 8 | 21051 |
| 9 | 87729 |
| 10 | 371394 |
| 11 | 1584946 |
| 12 | 6832849 |
| 13 | 29666458 |
| 14 | 129708627 |
| 15 | 570060258 |
| 16 | 2519251688 |
| 17 | 11178295951 |
| 18 | 49819703001 |
| 19 | 222797463880 |
| 20 | 999874253662 |
| 21 | 4500199157553 |
| 22 | 20313008617526 |
| 23 | 91912052460063 |
| 24 | 416903349368491 |
| 25 | 1894989864295280 |
| 26 | 8631524632718693 |
| 27 | 39387758710865188 |
[1,2,7,23,84,320,1262,5098,21051,87729,371394, 1584946,6832849,29666458,129708627,570060258, 2519251688,11178295951,49819703001,222797463880, 999874253662,4500199157553,20313008617526, 91912052460063,416903349368491,1894989864295280, 8631524632718693,39387758710865188] |