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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 26 |
| 7 | 76 |
| 8 | 232 |
| 9 | 750 |
| 10 | 2494 |
| 11 | 8524 |
| 12 | 29624 |
| 13 | 104468 |
| 14 | 372308 |
| 15 | 1338936 |
| 16 | 4850640 |
| 17 | 17685270 |
| 18 | 64834550 |
| 19 | 238843660 |
| 20 | 883677784 |
| 21 | 3282152588 |
| 22 | 12233309868 |
| 23 | 45741634536 |
| 24 | 171530482864 |
| 25 | 644953425740 |
| 26 | 2430975800876 |
| 27 | 9183681736376 |
| 28 | 34766785487152 |
| 29 | 131873995933480 |
[1,1,2,4,10,26,76,232,750,2494,8524,29624,104468, 372308,1338936,4850640,17685270,64834550, 238843660,883677784,3282152588,12233309868, 45741634536,171530482864,644953425740, 2430975800876,9183681736376,34766785487152, 131873995933480] |