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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 4 |
| 7 | 9 |
| 8 | 18 |
| 9 | 33 |
| 10 | 89 |
| 11 | 215 |
| 12 | 481 |
| 13 | 1486 |
| 14 | 4187 |
| 15 | 10974 |
| 16 | 37907 |
| 17 | 121114 |
| 18 | 362953 |
| 19 | 1385575 |
| 20 | 4924557 |
| 21 | 16494655 |
| 22 | 68685792 |
| 23 | 268113185 |
| 24 | 990074770 |
| 25 | 4455129525 |
| 26 | 18896355932 |
| 27 | 76116156873 |
| 28 | 367577989487 |
| 29 | 1679905933299 |
| 30 | 7313571105815 |
| 31 | 37669220146964 |
[1,1,1,1,2,3,4,9,18,33,89,215,481,1486,4187,10974, 37907,121114,362953,1385575,4924557,16494655, 68685792,268113185,990074770,4455129525, 18896355932,76116156873,367577989487, 1679905933299,7313571105815,37669220146964] |