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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 37 |
| 6 | 102 |
| 7 | 251 |
| 8 | 667 |
| 9 | 2011 |
| 10 | 6246 |
| 11 | 18686 |
| 12 | 54183 |
| 13 | 157438 |
| 14 | 466579 |
| 15 | 1400509 |
| 16 | 4202829 |
| 17 | 12556360 |
| 18 | 37480728 |
| 19 | 112227269 |
| 20 | 337221408 |
| 21 | 1014992763 |
| 22 | 3055963443 |
| 23 | 9203918219 |
| 24 | 27745375212 |
| 25 | 83736861040 |
| 26 | 252968402935 |
| 27 | 764733200716 |
| 28 | 2313088202001 |
| 29 | 7000425465331 |
[1,1,1,2,10,37,102,251,667,2011,6246,18686,54183, 157438,466579,1400509,4202829,12556360,37480728, 112227269,337221408,1014992763,3055963443, 9203918219,27745375212,83736861040,252968402935, 764733200716,2313088202001,7000425465331] |