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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 26 |
| 3 | 69 |
| 4 | 181 |
| 5 | 474 |
| 6 | 1241 |
| 7 | 3249 |
| 8 | 8506 |
| 9 | 22269 |
| 10 | 58301 |
| 11 | 152634 |
| 12 | 399601 |
| 13 | 1046169 |
| 14 | 2738906 |
| 15 | 7170549 |
| 16 | 18772741 |
| 17 | 49147674 |
| 18 | 128670281 |
| 19 | 336863169 |
| 20 | 881919226 |
| 21 | 2308894509 |
| 22 | 6044764301 |
| 23 | 15825398394 |
| 24 | 41431430881 |
| 25 | 108468894249 |
[1,9,26,69,181,474,1241,3249,8506,22269,58301, 152634,399601,1046169,2738906,7170549,18772741, 49147674,128670281,336863169,881919226,2308894509, 6044764301,15825398394,41431430881,108468894249] |