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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 3 |
| 2 | 3 |
| 3 | 10 |
| 4 | 21 |
| 5 | 55 |
| 6 | 136 |
| 7 | 351 |
| 8 | 903 |
| 9 | 2346 |
| 10 | 6105 |
| 11 | 15931 |
| 12 | 41616 |
| 13 | 108811 |
| 14 | 284635 |
| 15 | 744810 |
| 16 | 1949325 |
| 17 | 5102415 |
| 18 | 13356696 |
| 19 | 34965703 |
| 20 | 91537215 |
| 21 | 239640778 |
| 22 | 627376753 |
| 23 | 1642475955 |
| 24 | 4300029216 |
| 25 | 11257576275 |
| 26 | 29472642291 |
| 27 | 77160257866 |
| 28 | 202007981253 |
| 29 | 528863443111 |
| 30 | 1384581955240 |
[0,3,3,10,21,55,136,351,903,2346,6105,15931,41616, 108811,284635,744810,1949325,5102415,13356696, 34965703,91537215,239640778,627376753,1642475955, 4300029216,11257576275,29472642291,77160257866, 202007981253,528863443111,1384581955240] |