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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 14 |
| 7 | 38 |
| 8 | 88 |
| 9 | 217 |
| 10 | 506 |
| 11 | 1209 |
| 12 | 2810 |
| 13 | 6600 |
| 14 | 15308 |
| 15 | 35653 |
| 16 | 82532 |
| 17 | 191371 |
| 18 | 442428 |
| 19 | 1023499 |
| 20 | 2364324 |
| 21 | 5463084 |
| 22 | 12614628 |
| 23 | 29131729 |
| 24 | 67256334 |
| 25 | 155289747 |
| 26 | 358522126 |
| 27 | 827816037 |
| 28 | 1911447100 |
| 29 | 4414086763 |
| 30 | 10194246046 |
| 31 | 23546391253 |
[0,0,1,2,6,14,38,88,217,506,1209,2810,6600,15308, 35653,82532,191371,442428,1023499,2364324,5463084, 12614628,29131729,67256334,155289747,358522126, 827816037,1911447100,4414086763,10194246046, 23546391253] |