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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 15 |
| 6 | 28 |
| 7 | 150 |
| 8 | 301 |
| 9 | 567 |
| 10 | 1012 |
| 11 | 5957 |
| 12 | 11194 |
| 13 | 67220 |
| 14 | 131110 |
| 15 | 246180 |
| 16 | 446634 |
| 17 | 2790246 |
| 18 | 5228831 |
| 19 | 32849241 |
| 20 | 63172839 |
| 21 | 118285288 |
| 22 | 216048937 |
| 23 | 1389019151 |
| 24 | 2597508627 |
| 25 | 4752887314 |
| 26 | 8521006425 |
| 27 | 14986211764 |
| 28 | 25885275427 |
| 29 | 172796271571 |
| 30 | 305289220115 |
| 31 | 2029750359569 |
[1,0,1,2,3,15,28,150,301,567,1012,5957,11194, 67220,131110,246180,446634,2790246,5228831, 32849241,63172839,118285288,216048937,1389019151, 2597508627,4752887314,8521006425,14986211764, 25885275427,172796271571,305289220115, 2029750359569] |