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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 15 |
| 5 | 34 |
| 6 | 83 |
| 7 | 198 |
| 8 | 488 |
| 9 | 1202 |
| 10 | 3015 |
| 11 | 7608 |
| 12 | 19432 |
| 13 | 49994 |
| 14 | 129779 |
| 15 | 339176 |
| 16 | 892600 |
| 17 | 2362634 |
| 18 | 6288156 |
| 19 | 16816232 |
| 20 | 45170466 |
| 21 | 121812152 |
| 22 | 329679487 |
| 23 | 895171236 |
| 24 | 2437885058 |
| 25 | 6657311202 |
| 26 | 18224979884 |
| 27 | 50006899724 |
| 28 | 137502724754 |
[1,1,3,6,15,34,83,198,488,1202,3015,7608,19432, 49994,129779,339176,892600,2362634,6288156, 16816232,45170466,121812152,329679487,895171236, 2437885058,6657311202,18224979884,50006899724, 137502724754] |