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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 3 |
| 7 | 12 |
| 8 | 30 |
| 9 | 40 |
| 10 | 86 |
| 11 | 182 |
| 12 | 245 |
| 13 | 560 |
| 14 | 1270 |
| 15 | 1784 |
| 16 | 4070 |
| 17 | 9020 |
| 18 | 12782 |
| 19 | 28679 |
| 20 | 63518 |
| 21 | 91286 |
| 22 | 205478 |
| 23 | 455966 |
| 24 | 662151 |
| 25 | 1485624 |
| 26 | 3290520 |
| 27 | 4814672 |
| 28 | 10782222 |
| 29 | 23878212 |
| 30 | 35172819 |
| 31 | 78678468 |
| 32 | 174179258 |
| 33 | 257964134 |
| 34 | 576312440 |
[0,0,0,0,2,3,12,30,40,86,182,245,560,1270,1784, 4070,9020,12782,28679,63518,91286,205478,455966, 662151,1485624,3290520,4814672,10782222,23878212, 35172819,78678468,174179258,257964134,576312440] |