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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 25 |
| 6 | 68 |
| 7 | 185 |
| 8 | 503 |
| 9 | 1368 |
| 10 | 3719 |
| 11 | 10110 |
| 12 | 27482 |
| 13 | 74704 |
| 14 | 203067 |
| 15 | 551994 |
| 16 | 1500476 |
| 17 | 4078717 |
| 18 | 11087103 |
| 19 | 30137871 |
| 20 | 81923227 |
| 21 | 222690420 |
| 22 | 605335322 |
| 23 | 1645472006 |
| 24 | 4472856654 |
| 25 | 12158484964 |
| 26 | 33050188740 |
| 27 | 89839727479 |
| 28 | 244209698680 |
| 29 | 663830786256 |
| 30 | 1804479163452 |
| 31 | 4905082919845 |
[0,1,3,9,25,68,185,503,1368,3719,10110,27482, 74704,203067,551994,1500476,4078717,11087103, 30137871,81923227,222690420,605335322,1645472006, 4472856654,12158484964,33050188740,89839727479, 244209698680,663830786256,1804479163452, 4905082919845] |