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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 42 |
| 5 | 144 |
| 6 | 564 |
| 7 | 2064 |
| 8 | 7944 |
| 9 | 30252 |
| 10 | 117000 |
| 11 | 453192 |
| 12 | 1768480 |
| 13 | 6917504 |
| 14 | 27163232 |
| 15 | 106923648 |
| 16 | 421931308 |
| 17 | 1668250408 |
| 18 | 6608054656 |
| 19 | 26215991648 |
| 20 | 104154492224 |
| 21 | 414324786144 |
| 22 | 1650080158832 |
| 23 | 6578448714144 |
| 24 | 26251704924528 |
| 25 | 104850927048448 |
| 26 | 419119282453408 |
[1,3,10,42,144,564,2064,7944,30252,117000,453192, 1768480,6917504,27163232,106923648,421931308, 1668250408,6608054656,26215991648,104154492224, 414324786144,1650080158832,6578448714144, 26251704924528,104850927048448,419119282453408] |