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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 34 |
| 5 | 135 |
| 6 | 534 |
| 7 | 2162 |
| 8 | 9280 |
| 9 | 39708 |
| 10 | 172019 |
| 11 | 767169 |
| 12 | 3419711 |
| 13 | 15355346 |
| 14 | 70114015 |
| 15 | 320273041 |
| 16 | 1469955154 |
| 17 | 6819015777 |
| 18 | 31654184259 |
| 19 | 147435154707 |
| 20 | 691694048874 |
| 21 | 3247544114623 |
| 22 | 15285725308604 |
| 23 | 72318503653480 |
| 24 | 342407029336305 |
| 25 | 1624357336822081 |
| 26 | 7735077406352818 |
| 27 | 36860754582925005 |
[1,1,3,10,34,135,534,2162,9280,39708,172019, 767169,3419711,15355346,70114015,320273041, 1469955154,6819015777,31654184259,147435154707, 691694048874,3247544114623,15285725308604, 72318503653480,342407029336305,1624357336822081, 7735077406352818,36860754582925005] |