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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 64 |
| 5 | 340 |
| 6 | 1903 |
| 7 | 11053 |
| 8 | 65993 |
| 9 | 402527 |
| 10 | 2497439 |
| 11 | 15712220 |
| 12 | 100001459 |
| 13 | 642719263 |
| 14 | 4165537744 |
| 15 | 27193644061 |
| 16 | 178654643151 |
| 17 | 1180282875483 |
| 18 | 7836312619243 |
| 19 | 52259258911091 |
| 20 | 349902441457427 |
| 21 | 2351240866736891 |
| 22 | 15851508780927739 |
| 23 | 107187240225220684 |
| 24 | 726784821098903319 |
[1,1,3,13,64,340,1903,11053,65993,402527,2497439, 15712220,100001459,642719263,4165537744, 27193644061,178654643151,1180282875483, 7836312619243,52259258911091,349902441457427, 2351240866736891,15851508780927739, 107187240225220684,726784821098903319] |