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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 106 |
| 5 | 437 |
| 6 | 1929 |
| 7 | 8488 |
| 8 | 38396 |
| 9 | 174507 |
| 10 | 803900 |
| 11 | 3722663 |
| 12 | 17371905 |
| 13 | 81437630 |
| 14 | 383684351 |
| 15 | 1814422663 |
| 16 | 8611181387 |
| 17 | 40990036508 |
| 18 | 195652384453 |
| 19 | 936119745972 |
| 20 | 4488768349921 |
| 21 | 21566203619958 |
| 22 | 103800173160993 |
| 23 | 500414792081605 |
| 24 | 2416084626457006 |
| 25 | 11681304992422310 |
| 26 | 56548686955077475 |
| 27 | 274071984546734932 |
[1,2,7,25,106,437,1929,8488,38396,174507,803900, 3722663,17371905,81437630,383684351,1814422663, 8611181387,40990036508,195652384453,936119745972, 4488768349921,21566203619958,103800173160993, 500414792081605,2416084626457006, 11681304992422310,56548686955077475, 274071984546734932] |