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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 4 |
| 6 | 8 |
| 7 | 25 |
| 8 | 62 |
| 9 | 176 |
| 10 | 470 |
| 11 | 1311 |
| 12 | 3620 |
| 13 | 10094 |
| 14 | 28209 |
| 15 | 79236 |
| 16 | 223270 |
| 17 | 631240 |
| 18 | 1790213 |
| 19 | 5090995 |
| 20 | 14515788 |
| 21 | 41484907 |
| 22 | 118821599 |
| 23 | 341008317 |
| 24 | 980487770 |
| 25 | 2823961866 |
| 26 | 8146372122 |
| 27 | 23534556225 |
| 28 | 68083326558 |
| 29 | 197209108054 |
| 30 | 571910949743 |
| 31 | 1660395053569 |
| 32 | 4825540091342 |
[0,0,1,1,4,8,25,62,176,470,1311,3620,10094,28209, 79236,223270,631240,1790213,5090995,14515788, 41484907,118821599,341008317,980487770,2823961866, 8146372122,23534556225,68083326558,197209108054, 571910949743,1660395053569,4825540091342] |