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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 4 |
| 7 | 6 |
| 8 | 14 |
| 9 | 28 |
| 10 | 60 |
| 11 | 125 |
| 12 | 263 |
| 13 | 558 |
| 14 | 1181 |
| 15 | 2513 |
| 16 | 5339 |
| 17 | 11392 |
| 18 | 24290 |
| 19 | 51926 |
| 20 | 111017 |
| 21 | 237757 |
| 22 | 509404 |
| 23 | 1092713 |
| 24 | 2345256 |
| 25 | 5038015 |
| 26 | 10828720 |
| 27 | 23291759 |
| 28 | 50126055 |
| 29 | 107939753 |
| 30 | 232550011 |
| 31 | 501270200 |
| 32 | 1080996244 |
| 33 | 2332221316 |
| 34 | 5033764628 |
| 35 | 10868950676 |
| 36 | 23476998980 |
| 37 | 50728408182 |
| 38 | 109649040738 |
| 39 | 237081174662 |
| 40 | 512767906801 |
| 41 | 1109354495908 |
[0,1,0,1,1,4,6,14,28,60,125,263,558,1181,2513, 5339,11392,24290,51926,111017,237757,509404, 1092713,2345256,5038015,10828720,23291759, 50126055,107939753,232550011,501270200,1080996244, 2332221316,5033764628,10868950676,23476998980, 50728408182,109649040738,237081174662, 512767906801,1109354495908] |