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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 9 |
| 4 | 49 |
| 5 | 225 |
| 6 | 1041 |
| 7 | 4873 |
| 8 | 22817 |
| 9 | 106753 |
| 10 | 499425 |
| 11 | 2336585 |
| 12 | 10931921 |
| 13 | 51145825 |
| 14 | 239289457 |
| 15 | 1119533257 |
| 16 | 5237818689 |
| 17 | 24505519873 |
| 18 | 114650876097 |
| 19 | 536402551689 |
| 20 | 2509598769265 |
| 21 | 11741342323937 |
| 22 | 54932733173713 |
| 23 | 257006830281609 |
[1,1,1,9,49,225,1041,4873,22817,106753,499425, 2336585,10931921,51145825,239289457,1119533257, 5237818689,24505519873,114650876097,536402551689, 2509598769265,11741342323937,54932733173713, 257006830281609] |