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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 8 |
| 4 | 31 |
| 5 | 146 |
| 6 | 754 |
| 7 | 4168 |
| 8 | 24387 |
| 9 | 149878 |
| 10 | 961735 |
| 11 | 6413730 |
| 12 | 44305495 |
| 13 | 316289264 |
| 14 | 2329690081 |
| 15 | 17685913364 |
| 16 | 138276568051 |
| 17 | 1112831978494 |
| 18 | 9214885055084 |
| 19 | 78482008660596 |
| 20 | 687242245179732 |
| 21 | 6184901074959982 |
| 22 | 57179080181866903 |
| 23 | 542740440965244192 |
[1,2,3,8,31,146,754,4168,24387,149878,961735, 6413730,44305495,316289264,2329690081,17685913364, 138276568051,1112831978494,9214885055084, 78482008660596,687242245179732,6184901074959982, 57179080181866903,542740440965244192] |