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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 19 |
| 4 | 61 |
| 5 | 197 |
| 6 | 638 |
| 7 | 2069 |
| 8 | 6714 |
| 9 | 21794 |
| 10 | 70755 |
| 11 | 229725 |
| 12 | 745889 |
| 13 | 2421850 |
| 14 | 7863641 |
| 15 | 25532994 |
| 16 | 82904974 |
| 17 | 269190547 |
| 18 | 874055885 |
| 19 | 2838041117 |
| 20 | 9215060822 |
| 21 | 29921113293 |
| 22 | 97153242650 |
| 23 | 315454594314 |
| 24 | 1024274628963 |
| 25 | 3325798821581 |
| 26 | 10798800928441 |
| 27 | 35063486341682 |
[1,2,6,19,61,197,638,2069,6714,21794,70755,229725, 745889,2421850,7863641,25532994,82904974, 269190547,874055885,2838041117,9215060822, 29921113293,97153242650,315454594314, 1024274628963,3325798821581,10798800928441, 35063486341682] |