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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 22 |
| 5 | 66 |
| 6 | 227 |
| 7 | 768 |
| 8 | 2771 |
| 9 | 10025 |
| 10 | 37661 |
| 11 | 142117 |
| 12 | 548827 |
| 13 | 2135363 |
| 14 | 8429552 |
| 15 | 33539945 |
| 16 | 134793466 |
| 17 | 545473164 |
| 18 | 2224521240 |
| 19 | 9126088552 |
| 20 | 37669774713 |
| 21 | 156291183756 |
| 22 | 651703333129 |
| 23 | 2729564106197 |
| 24 | 11480817576072 |
| 25 | 48475175596266 |
| 26 | 205419727220096 |
| 27 | 873413070037042 |
| 28 | 3725364574591882 |
[1,1,3,7,22,66,227,768,2771,10025,37661,142117, 548827,2135363,8429552,33539945,134793466, 545473164,2224521240,9126088552,37669774713, 156291183756,651703333129,2729564106197, 11480817576072,48475175596266,205419727220096, 873413070037042,3725364574591882] |