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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 40 |
| 5 | 148 |
| 6 | 555 |
| 7 | 2100 |
| 8 | 7997 |
| 9 | 30605 |
| 10 | 117602 |
| 11 | 453421 |
| 12 | 1753176 |
| 13 | 6795248 |
| 14 | 26393431 |
| 15 | 102702230 |
| 16 | 400277998 |
| 17 | 1562292741 |
| 18 | 6105426033 |
| 19 | 23887275883 |
| 20 | 93554945414 |
| 21 | 366754396228 |
| 22 | 1438986625349 |
| 23 | 5650409534767 |
| 24 | 22203298031827 |
| 25 | 87306238753663 |
| 26 | 343511939707274 |
[0,1,3,11,40,148,555,2100,7997,30605,117602, 453421,1753176,6795248,26393431,102702230, 400277998,1562292741,6105426033,23887275883, 93554945414,366754396228,1438986625349, 5650409534767,22203298031827,87306238753663, 343511939707274] |