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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 41 |
| 6 | 123 |
| 7 | 374 |
| 8 | 1147 |
| 9 | 3538 |
| 10 | 10958 |
| 11 | 34042 |
| 12 | 105997 |
| 13 | 330632 |
| 14 | 1032781 |
| 15 | 3229714 |
| 16 | 10109310 |
| 17 | 31667245 |
| 18 | 99260192 |
| 19 | 311294876 |
| 20 | 976709394 |
| 21 | 3065676758 |
| 22 | 9625674442 |
| 23 | 30231524869 |
| 24 | 94972205349 |
| 25 | 298419158008 |
| 26 | 937861780439 |
| 27 | 2947969125284 |
[1,1,2,5,14,41,123,374,1147,3538,10958,34042, 105997,330632,1032781,3229714,10109310,31667245, 99260192,311294876,976709394,3065676758, 9625674442,30231524869,94972205349,298419158008, 937861780439,2947969125284] |