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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 102 |
| 5 | 421 |
| 6 | 1833 |
| 7 | 8055 |
| 8 | 36333 |
| 9 | 165105 |
| 10 | 761383 |
| 11 | 3531580 |
| 12 | 16531186 |
| 13 | 77736848 |
| 14 | 367792638 |
| 15 | 1746466460 |
| 16 | 8329088373 |
| 17 | 39838754439 |
| 18 | 191165146280 |
| 19 | 919486724021 |
| 20 | 4433590609255 |
| 21 | 21419834806102 |
| 22 | 103687748482389 |
| 23 | 502743056244639 |
| 24 | 2441491903750180 |
| 25 | 11872958808117098 |
| 26 | 57814141613740897 |
| 27 | 281847208285495504 |
[1,2,7,25,102,421,1833,8055,36333,165105,761383, 3531580,16531186,77736848,367792638,1746466460, 8329088373,39838754439,191165146280,919486724021, 4433590609255,21419834806102,103687748482389, 502743056244639,2441491903750180, 11872958808117098,57814141613740897, 281847208285495504] |