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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 6 |
| 6 | 13 |
| 7 | 28 |
| 8 | 64 |
| 9 | 153 |
| 10 | 379 |
| 11 | 939 |
| 12 | 2385 |
| 13 | 6121 |
| 14 | 15871 |
| 15 | 41529 |
| 16 | 109509 |
| 17 | 290607 |
| 18 | 775842 |
| 19 | 2081874 |
| 20 | 5612176 |
| 21 | 15191329 |
| 22 | 41274052 |
[1,1,2,3,6,13,28,64,153,379,939,2385,6121,15871, 41529,109509,290607,775842,2081874,5612176, 15191329,41274052] |