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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 0 |
| 5 | 2 |
| 6 | 1 |
| 7 | 3 |
| 8 | 5 |
| 9 | 7 |
| 10 | 15 |
| 11 | 20 |
| 12 | 48 |
| 13 | 60 |
| 14 | 156 |
| 15 | 205 |
| 16 | 489 |
| 17 | 761 |
| 18 | 1572 |
| 19 | 2796 |
| 20 | 5357 |
| 21 | 10174 |
| 22 | 19021 |
| 23 | 37272 |
| 24 | 69375 |
| 25 | 137759 |
| 26 | 258444 |
| 27 | 513696 |
| 28 | 976890 |
| 29 | 1934900 |
| 30 | 3727164 |
| 31 | 7358675 |
| 32 | 14316861 |
| 33 | 28217028 |
| 34 | 55288907 |
| 35 | 108942267 |
| 36 | 214462953 |
| 37 | 422973649 |
[0,0,1,0,2,1,3,5,7,15,20,48,60,156,205,489,761, 1572,2796,5357,10174,19021,37272,69375,137759, 258444,513696,976890,1934900,3727164,7358675, 14316861,28217028,55288907,108942267,214462953, 422973649] |