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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 28 |
| 4 | 91 |
| 5 | 308 |
| 6 | 1078 |
| 7 | 3871 |
| 8 | 14161 |
| 9 | 52479 |
| 10 | 196196 |
| 11 | 737793 |
| 12 | 2785160 |
| 13 | 10540390 |
| 14 | 39955041 |
| 15 | 151615947 |
| 16 | 575723785 |
| 17 | 2187128524 |
| 18 | 8311078307 |
| 19 | 31587815308 |
| 20 | 120069510526 |
| 21 | 456434707519 |
| 22 | 1735184512425 |
| 23 | 6596692255391 |
| 24 | 25079305566420 |
[1,3,9,28,91,308,1078,3871,14161,52479,196196, 737793,2785160,10540390,39955041,151615947, 575723785,2187128524,8311078307,31587815308, 120069510526,456434707519,1735184512425, 6596692255391,25079305566420] |