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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 35 |
| 4 | 166 |
| 5 | 727 |
| 6 | 3538 |
| 7 | 16294 |
| 8 | 80160 |
| 9 | 378927 |
| 10 | 1874930 |
| 11 | 9000443 |
| 12 | 44683110 |
| 13 | 216630208 |
| 14 | 1077697787 |
| 15 | 5260220811 |
| 16 | 26204060817 |
| 17 | 128518455419 |
| 18 | 640809487729 |
| 19 | 3154046495137 |
| 20 | 15736623881298 |
| 21 | 77664193244089 |
| 22 | 387673662776003 |
| 23 | 1917272347984752 |
| 24 | 9573667095262513 |
| 25 | 47425770367580942 |
| 26 | 236876010551566137 |
[1,2,9,35,166,727,3538,16294,80160,378927,1874930, 9000443,44683110,216630208,1077697787,5260220811, 26204060817,128518455419,640809487729, 3154046495137,15736623881298,77664193244089, 387673662776003,1917272347984752,9573667095262513, 47425770367580942,236876010551566137] |