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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 3 |
| 6 | 8 |
| 7 | 19 |
| 8 | 47 |
| 9 | 119 |
| 10 | 309 |
| 11 | 805 |
| 12 | 2115 |
| 13 | 5594 |
| 14 | 14920 |
| 15 | 40037 |
| 16 | 108068 |
| 17 | 293124 |
| 18 | 798739 |
| 19 | 2185380 |
| 20 | 6001797 |
| 21 | 16538728 |
| 22 | 45716315 |
| 23 | 126727586 |
| 24 | 352214041 |
| 25 | 981269274 |
| 26 | 2739925455 |
| 27 | 7666335708 |
| 28 | 21491822234 |
| 29 | 60358497108 |
| 30 | 169798015580 |
| 31 | 478420350367 |
[0,0,0,1,3,8,19,47,119,309,805,2115,5594,14920, 40037,108068,293124,798739,2185380,6001797, 16538728,45716315,126727586,352214041,981269274, 2739925455,7666335708,21491822234,60358497108, 169798015580,478420350367] |