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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 15 |
| 7 | 36 |
| 8 | 91 |
| 9 | 232 |
| 10 | 603 |
| 11 | 1585 |
| 12 | 4213 |
| 13 | 11298 |
| 14 | 30537 |
| 15 | 83097 |
| 16 | 227475 |
| 17 | 625992 |
| 18 | 1730787 |
| 19 | 4805595 |
| 20 | 13393689 |
| 21 | 37458330 |
| 22 | 105089229 |
| 23 | 295673994 |
| 24 | 834086421 |
| 25 | 2358641376 |
| 26 | 6684761125 |
| 27 | 18985057351 |
| 28 | 54022715451 |
| 29 | 154000562758 |
| 30 | 439742222071 |
| 31 | 1257643249140 |
[1,0,1,1,3,6,15,36,91,232,603,1585,4213,11298, 30537,83097,227475,625992,1730787,4805595, 13393689,37458330,105089229,295673994,834086421, 2358641376,6684761125,18985057351,54022715451, 154000562758,439742222071,1257643249140] |