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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 2 |
| 7 | 5 |
| 8 | 5 |
| 9 | 20 |
| 10 | 35 |
| 11 | 75 |
| 12 | 154 |
| 13 | 336 |
| 14 | 730 |
| 15 | 1570 |
| 16 | 3394 |
| 17 | 7339 |
| 18 | 16085 |
| 19 | 35015 |
| 20 | 76269 |
| 21 | 164821 |
| 22 | 359704 |
| 23 | 782004 |
| 24 | 1696804 |
| 25 | 3668860 |
| 26 | 7953962 |
| 27 | 17184203 |
| 28 | 37093184 |
| 29 | 79825297 |
| 30 | 171824175 |
| 31 | 368838299 |
| 32 | 790404448 |
| 33 | 1690297309 |
| 34 | 3610816466 |
| 35 | 7696144659 |
| 36 | 16374004711 |
| 37 | 34766160358 |
[1,1,0,0,0,1,2,5,5,20,35,75,154,336,730,1570,3394, 7339,16085,35015,76269,164821,359704,782004, 1696804,3668860,7953962,17184203,37093184, 79825297,171824175,368838299,790404448,1690297309, 3610816466,7696144659,16374004711,34766160358] |