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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 10 |
| 5 | 26 |
| 6 | 86 |
| 7 | 312 |
| 8 | 1022 |
| 9 | 3978 |
| 10 | 14098 |
| 11 | 55214 |
| 12 | 209256 |
| 13 | 825384 |
| 14 | 3259848 |
| 15 | 13047190 |
| 16 | 52796942 |
| 17 | 214867958 |
| 18 | 883609140 |
| 19 | 3650644490 |
| 20 | 15200444924 |
| 21 | 63591578852 |
| 22 | 267560620976 |
| 23 | 1130884163454 |
| 24 | 4801237259556 |
| 25 | 20467269154810 |
| 26 | 87575978537798 |
| 27 | 376056564410360 |
| 28 | 1620031193788260 |
| 29 | 7000548312843696 |
[1,0,2,2,10,26,86,312,1022,3978,14098,55214, 209256,825384,3259848,13047190,52796942,214867958, 883609140,3650644490,15200444924,63591578852, 267560620976,1130884163454,4801237259556, 20467269154810,87575978537798,376056564410360, 1620031193788260,7000548312843696] |