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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 39 |
| 5 | 145 |
| 6 | 630 |
| 7 | 2593 |
| 8 | 11591 |
| 9 | 50017 |
| 10 | 229816 |
| 11 | 1027680 |
| 12 | 4787417 |
| 13 | 21844486 |
| 14 | 103089050 |
| 15 | 478192777 |
| 16 | 2274130170 |
| 17 | 10665707770 |
| 18 | 51086135767 |
| 19 | 241825054742 |
| 20 | 1163848294068 |
| 21 | 5546693978070 |
| 22 | 26813667994663 |
| 23 | 128532843066514 |
| 24 | 623362741860976 |
| 25 | 3001574315408743 |
| 26 | 14600655776691757 |
| 27 | 70579346335119111 |
[1,1,3,10,39,145,630,2593,11591,50017,229816, 1027680,4787417,21844486,103089050,478192777, 2274130170,10665707770,51086135767,241825054742, 1163848294068,5546693978070,26813667994663, 128532843066514,623362741860976,3001574315408743, 14600655776691757,70579346335119111] |