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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 5 |
| 6 | 22 |
| 7 | 64 |
| 8 | 198 |
| 9 | 710 |
| 10 | 2332 |
| 11 | 8105 |
| 12 | 28665 |
| 13 | 100653 |
| 14 | 361104 |
| 15 | 1301180 |
| 16 | 4713267 |
| 17 | 17217021 |
| 18 | 63140534 |
| 19 | 232702261 |
| 20 | 861507251 |
| 21 | 3200666821 |
| 22 | 11933894310 |
| 23 | 44636509320 |
| 24 | 167427781950 |
| 25 | 629691033738 |
| 26 | 2373987233286 |
| 27 | 8970240131032 |
| 28 | 33965443165016 |
| 29 | 128857452216256 |
[0,1,0,1,3,5,22,64,198,710,2332,8105,28665,100653, 361104,1301180,4713267,17217021,63140534, 232702261,861507251,3200666821,11933894310, 44636509320,167427781950,629691033738, 2373987233286,8970240131032,33965443165016, 128857452216256] |